The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform

Chengguo Xing - One of the best experts on this subject based on the ideXlab platform.

  • A stable isotope dilution tandem mass spectrometry method of major kavalactones and its applications
    PLOS ONE, 2018
    Co-Authors: Yi Wang, Shainnel O. Eans, Heather M. Stacy, Sreekanth Narayanapillai, Linda G. Haddad, Jay P. Mclaughlin, Naomi Fujioka, Abhisheak Sharma, Bonnie A. Avery, Chengguo Xing
    Abstract:

    Kava is regaining its popularity with detailed characterizations warranted. We developed an ultraperformance liquid chromatography high-resolution tandem mass spectrometry (UPLC-MS/MS) method for major kavalactones (kavain, dihydrokavain, Methysticin, dihydroMethysticin and desmethoxyyangonin) with excellent selectivity and specificity. The method has been validated for different matrices following the Food and Drug Administration guidance of analytical procedures and methods validation. The scope of this method has been demonstrated by quantifying these kavalactones in two kava products, characterizing their tissue distribution and pharmacokinetics in mice, and detecting their presence in human urines and plasmas upon kava intake. As expected, the abundances of these kavalactones differed significantly in kava products. All of them exhibited a large volume of distribution with extensive tissue affinity and adequate mean residence time (MRT) in mice. This method also successfully quantified these kavalactones in human body fluids upon kava consumption at the recommended human dose. This UPLC-MS/MS method therefore can be used to characterize kava products and its pharmacokinetics in animals and in humans.

  • identification of Methysticin as a potent and non toxic nf κb inhibitor from kava potentially responsible for kava s chemopreventive activity
    Bioorganic & Medicinal Chemistry Letters, 2009
    Co-Authors: Ahmad Ali Shaik, Lampi Hermanson David, Chengguo Xing
    Abstract:

    Nuclear factor-kappaB (NF-kappaB) is a transcription factor that plays an essential role in cancer development. The results of our recent chemopreventive study demonstrate that kava, a beverage in the South Pacific Islands, suppresses NF-kappaB activation in lung adenoma tissues, potentially a mechanism responsible for kava's chemopreventive activity. Methysticin is identified as a potent NF-kappaB inhibitor in kava with minimum toxicity. Other kava constituents, including four kavalactones of similar structures to Methysticin, demonstrate minimum activities in inhibiting NF-kappaB.

Michael B. Lilly - One of the best experts on this subject based on the ideXlab platform.

  • Kava Components Down-Regulate Expression of AR and AR Splice Variants and Reduce Growth in Patient-Derived Prostate Cancer Xenografts in Mice
    2016
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    Men living in Fiji and drinking kava have low incidence of prostate cancer (PCa). However, the PCa incidence among Fijian men who had migrated to Australia, increased by 5.1-fold. We therefore examined the potential effects of kava root extracts and its active components (kavalactones and flavokawains) on PCa growth and androgen receptor (AR) expression. PCa cell lines (LNCaP, LAPC-4, 22Rv1, C4-2B, DU145 and PC-3) with different AR expression, and a transformed prostate myofibroblast cell line (WPMY-1), were treated with a commercial kava extract, kavalactones (kawain, 5969-dehydrokawain, yangonin, Methysticin) and flavokawain B. Expression of AR and its target genes (PSA and TMPRSS2) was examined. Two novel patient-derived PCa xenograft models from high grade PCa specimens were established by implanting the specimens into nude mice and passing tumor pieces through subcutaneous injection in nude mice, and then treated with kava extract and flavokawain B to examine their effects on tumor growth, AR expression and serum PSA levels. The kava extract an

  • The kava root extract and kavalactones down-regulate expression of AR and AR target genes (PSA and TMPRSS2) via accelerating the degradation of AR protein.
    2013
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    (A). C4-2B cells were treated with 0.1%DMSO, kava root extract, dehydrokawain, kawain, yangonin and Methysticin for 8 hours. mRNA levels of AR and AR target genes (PSA and TMPRSS2) were determined by real-time RT-PCR. Bars are means ± SD of three independent quantitative measures. Kava root extract and kavalactones significantly decrease mRNA expression of AR target genes (Student t test, P0.05). (B) and (C). The protein expression of AR and PSA in LNCaP and C4-2B cells after indicated treatments at a concentration of their IC50 s for 16 hours was analyzed by Western blot. α-Tubulin was detected as a loading control. A representative blot was shown from three independent experiments. Y = yangonin; M = Methysticin; D = 5′6;-dehydrokawain; K = kawain, KRE = kava root extract. (D). C4-2B cells were pretreated with 10 µg/ml cycloheximide for 2 hours and then supplemented with kava root extract or 5′6;-dehydrokawain at a concentration of their IC50 s for different periods of time. After treatments, AR protein levels were analyzed by Western blotting and semi-quantified by densitometry measurement. A representative blot was shown from three independent experiments.

  • The effect of the kava root extract and its active components on the growth of PCa cell lines (C4-2B, LNCaP, 22Rv1, LAPC-4, DU145 and PC3) and a prostate myofibroblast WPMY-1.
    2013
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    Cells in 24-well culture plates were treated with 0.1% DMSO, the kava root extract, kawain, 5′, 6′-dehydrokawain, yangonin, Methysticin, or flavokawain B (FKB) at the indicated doses. After 72 hours of treatment, cell densities were measured by MTT assay. Each point is the mean of values from four independent plates; bars, SD. Each sample was counted in duplicate. IC50 s were estimated by dose-response curves.

  • Kava Components Down-Regulate Expression of AR and AR Splice Variants and Reduce Growth in Patient-Derived Prostate Cancer Xenografts in Mice
    PloS one, 2012
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    Men living in Fiji and drinking kava have low incidence of prostate cancer (PCa). However, the PCa incidence among Fijian men who had migrated to Australia, increased by 5.1-fold. We therefore examined the potential effects of kava root extracts and its active components (kavalactones and flavokawains) on PCa growth and androgen receptor (AR) expression. PCa cell lines (LNCaP, LAPC-4, 22Rv1, C4-2B, DU145 and PC-3) with different AR expression, and a transformed prostate myofibroblast cell line (WPMY-1), were treated with a commercial kava extract, kavalactones (kawain, 5′6′-dehydrokawain, yangonin, Methysticin) and flavokawain B. Expression of AR and its target genes (PSA and TMPRSS2) was examined. Two novel patient-derived PCa xenograft models from high grade PCa specimens were established by implanting the specimens into nude mice and passing tumor pieces through subcutaneous injection in nude mice, and then treated with kava extract and flavokawain B to examine their effects on tumor growth, AR expression and serum PSA levels. The kava extract and flavokawain B effectively down-regulated the expression of both the full-length AR and AR splice variants. The kava extract and kavalactones accelerated AR protein degradation, while flavokawain B inhibited AR mRNA transcription via decreasing Sp1 expression and the binding of Sp1 to the AR promoter. The kava root extract and flavokawain B reduce tumor growth, AR expression in tumor tissues and levels of serum PSA in the patient-derived PCa xenograft models. These results suggest a potential usefulness of a safe kava product or its active components for prevention and treatment of advanced PCa by targeting AR.

  • Kava components downregulate expression of AR and AR splice variants and reduce growth in patientderived prostate cancer xenografts in mice. PLoS One 7: e31213
    2012
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    Men living in Fiji and drinking kava have low incidence of prostate cancer (PCa). However, the PCa incidence among Fijian men who had migrated to Australia, increased by 5.1-fold. We therefore examined the potential effects of kava root extracts and its active components (kavalactones and flavokawains) on PCa growth and androgen receptor (AR) expression. PCa cell lines (LNCaP, LAPC-4, 22Rv1, C4-2B, DU145 and PC-3) with different AR expression, and a transformed prostate myofibroblast cell line (WPMY-1), were treated with a commercial kava extract, kavalactones (kawain, 5969-dehydrokawain, yangonin, Methysticin) and flavokawain B. Expression of AR and its target genes (PSA and TMPRSS2) was examined. Two novel patient-derived PCa xenograft models from high grade PCa specimens were established by implanting the specimens into nude mice and passing tumor pieces through subcutaneous injection in nude mice, and then treated with kava extract and flavokawain B to examine their effects on tumor growth, AR expression and serum PSA levels. The kava extract and flavokawain B effectively down-regulated the expression of both the full-length AR and AR splice variants. The kava extract and kavalactones accelerated AR protein degradation, while flavokawain B inhibited AR mRNA transcription via decreasing Sp1 expression and the binding of Sp1 to the AR promoter. The kava root extract and flavokawain B reduce tumor growth, AR expression in tumor tissues and levels of serum PSA in the patient-derived PCa xenograft models. These results suggest a potential usefulness of a safe kava product or its active components for prevention and treatment of advanced PCa b

Josef Krieglstein - One of the best experts on this subject based on the ideXlab platform.

  • Extract of kava (Piper methysticum) and its Methysticin constituents protect brain tissue against ischemic damage in rodents
    European Journal of Pharmacology, 1992
    Co-Authors: Cord Backhauβ, Josef Krieglstein
    Abstract:

    Abstract The purpose of the present study was to test whether kava extract and its constituents kawain, dihydrokawain, Methysticin, dihydroMethysticin and yangonin provide protection against ischemic brain damage. To this end, we used a model of focal cerebral ischemia in mice and rats. Ischemia was induced by microbipolar coagulation of the left middle cerebral artery (MCA). To quantify the size of the lesion in mice, the area of the infarct on the brain surface was assessed planimetrically 48 h after MCA occlusion by transcardial perfusion of carbon black. In the rat model infarct volume was determined 48 h after MCA occlusion by planimetric analysis and subsequent integration of the infarct areas on serial coronal slices. Compounds were administered i.p., except the kava extract, which was administered orally. The effects of the kava extract and its constituents were compared with those produced by the typical anticonvulsant, memantine. The kava extract, Methysticin and dihydroMethysticin produced effects similar to those of the reference substance memantine. The kava extract (150 mg/kg, 1 h before ischemia) diminished the infarct area (P

  • extract of kava piper methysticum and its Methysticin constituents protect brain tissue against ischemic damage in rodents
    European Journal of Pharmacology, 1992
    Co-Authors: Cord Backhauβ, Josef Krieglstein
    Abstract:

    The purpose of the present study was to test whether kava extract and its constituents kawain, dihydrokawain, Methysticin, dihydroMethysticin and yangonin provide protection against ischemic brain damage. To this end, we used a model of focal cerebral ischemia in mice and rats. Ischemia was induced by microbipolar coagulation of the left middle cerebral artery (MCA). To quantify the size of the lesion in mice, the area of the infarct on the brain surface was assessed planimetrically 48 h after MCA occlusion by transcardial perfusion of carbon black. In the rat model infarct volume was determined 48 h after MCA occlusion by planimetric analysis and subsequent integration of the infarct areas on serial coronal slices. Compounds were administered i.p., except the kava extract, which was administered orally. The effects of the kava extract and its constituents were compared with those produced by the typical anticonvulsant, memantine. The kava extract, Methysticin and dihydroMethysticin produced effects similar to those of the reference substance memantine. The kava extract (150 mg/kg, 1 h before ischemia) diminished the infarct area (P less than 0.05) in mouse brains and the infarct volume (P less than 0.05) in rat brains. Methysticin, dihydroMethysticin (both 10 and 30 mg/kg, 15 min before ischemia) and memantine (20 mg/kg, 30 min before ischemia) significantly reduced the infarct area in mouse brains. All other compounds failed to produce a beneficial effect on the infarct area in mouse brains. In conclusion, the kava extract exhibited neuroprotective activity, which was probably mediated by its constituents Methysticin and dihydroMethysticin.

Zhongbo Liu - One of the best experts on this subject based on the ideXlab platform.

  • Kava Components Down-Regulate Expression of AR and AR Splice Variants and Reduce Growth in Patient-Derived Prostate Cancer Xenografts in Mice
    2016
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    Men living in Fiji and drinking kava have low incidence of prostate cancer (PCa). However, the PCa incidence among Fijian men who had migrated to Australia, increased by 5.1-fold. We therefore examined the potential effects of kava root extracts and its active components (kavalactones and flavokawains) on PCa growth and androgen receptor (AR) expression. PCa cell lines (LNCaP, LAPC-4, 22Rv1, C4-2B, DU145 and PC-3) with different AR expression, and a transformed prostate myofibroblast cell line (WPMY-1), were treated with a commercial kava extract, kavalactones (kawain, 5969-dehydrokawain, yangonin, Methysticin) and flavokawain B. Expression of AR and its target genes (PSA and TMPRSS2) was examined. Two novel patient-derived PCa xenograft models from high grade PCa specimens were established by implanting the specimens into nude mice and passing tumor pieces through subcutaneous injection in nude mice, and then treated with kava extract and flavokawain B to examine their effects on tumor growth, AR expression and serum PSA levels. The kava extract an

  • The kava root extract and kavalactones down-regulate expression of AR and AR target genes (PSA and TMPRSS2) via accelerating the degradation of AR protein.
    2013
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    (A). C4-2B cells were treated with 0.1%DMSO, kava root extract, dehydrokawain, kawain, yangonin and Methysticin for 8 hours. mRNA levels of AR and AR target genes (PSA and TMPRSS2) were determined by real-time RT-PCR. Bars are means ± SD of three independent quantitative measures. Kava root extract and kavalactones significantly decrease mRNA expression of AR target genes (Student t test, P0.05). (B) and (C). The protein expression of AR and PSA in LNCaP and C4-2B cells after indicated treatments at a concentration of their IC50 s for 16 hours was analyzed by Western blot. α-Tubulin was detected as a loading control. A representative blot was shown from three independent experiments. Y = yangonin; M = Methysticin; D = 5′6;-dehydrokawain; K = kawain, KRE = kava root extract. (D). C4-2B cells were pretreated with 10 µg/ml cycloheximide for 2 hours and then supplemented with kava root extract or 5′6;-dehydrokawain at a concentration of their IC50 s for different periods of time. After treatments, AR protein levels were analyzed by Western blotting and semi-quantified by densitometry measurement. A representative blot was shown from three independent experiments.

  • The effect of the kava root extract and its active components on the growth of PCa cell lines (C4-2B, LNCaP, 22Rv1, LAPC-4, DU145 and PC3) and a prostate myofibroblast WPMY-1.
    2013
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    Cells in 24-well culture plates were treated with 0.1% DMSO, the kava root extract, kawain, 5′, 6′-dehydrokawain, yangonin, Methysticin, or flavokawain B (FKB) at the indicated doses. After 72 hours of treatment, cell densities were measured by MTT assay. Each point is the mean of values from four independent plates; bars, SD. Each sample was counted in duplicate. IC50 s were estimated by dose-response curves.

  • Kava Components Down-Regulate Expression of AR and AR Splice Variants and Reduce Growth in Patient-Derived Prostate Cancer Xenografts in Mice
    PloS one, 2012
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    Men living in Fiji and drinking kava have low incidence of prostate cancer (PCa). However, the PCa incidence among Fijian men who had migrated to Australia, increased by 5.1-fold. We therefore examined the potential effects of kava root extracts and its active components (kavalactones and flavokawains) on PCa growth and androgen receptor (AR) expression. PCa cell lines (LNCaP, LAPC-4, 22Rv1, C4-2B, DU145 and PC-3) with different AR expression, and a transformed prostate myofibroblast cell line (WPMY-1), were treated with a commercial kava extract, kavalactones (kawain, 5′6′-dehydrokawain, yangonin, Methysticin) and flavokawain B. Expression of AR and its target genes (PSA and TMPRSS2) was examined. Two novel patient-derived PCa xenograft models from high grade PCa specimens were established by implanting the specimens into nude mice and passing tumor pieces through subcutaneous injection in nude mice, and then treated with kava extract and flavokawain B to examine their effects on tumor growth, AR expression and serum PSA levels. The kava extract and flavokawain B effectively down-regulated the expression of both the full-length AR and AR splice variants. The kava extract and kavalactones accelerated AR protein degradation, while flavokawain B inhibited AR mRNA transcription via decreasing Sp1 expression and the binding of Sp1 to the AR promoter. The kava root extract and flavokawain B reduce tumor growth, AR expression in tumor tissues and levels of serum PSA in the patient-derived PCa xenograft models. These results suggest a potential usefulness of a safe kava product or its active components for prevention and treatment of advanced PCa by targeting AR.

  • Kava components downregulate expression of AR and AR splice variants and reduce growth in patientderived prostate cancer xenografts in mice. PLoS One 7: e31213
    2012
    Co-Authors: Zhongbo Liu, Christopher A. Blair, Zheng Sun, Jun Xie, Michael B. Lilly
    Abstract:

    Men living in Fiji and drinking kava have low incidence of prostate cancer (PCa). However, the PCa incidence among Fijian men who had migrated to Australia, increased by 5.1-fold. We therefore examined the potential effects of kava root extracts and its active components (kavalactones and flavokawains) on PCa growth and androgen receptor (AR) expression. PCa cell lines (LNCaP, LAPC-4, 22Rv1, C4-2B, DU145 and PC-3) with different AR expression, and a transformed prostate myofibroblast cell line (WPMY-1), were treated with a commercial kava extract, kavalactones (kawain, 5969-dehydrokawain, yangonin, Methysticin) and flavokawain B. Expression of AR and its target genes (PSA and TMPRSS2) was examined. Two novel patient-derived PCa xenograft models from high grade PCa specimens were established by implanting the specimens into nude mice and passing tumor pieces through subcutaneous injection in nude mice, and then treated with kava extract and flavokawain B to examine their effects on tumor growth, AR expression and serum PSA levels. The kava extract and flavokawain B effectively down-regulated the expression of both the full-length AR and AR splice variants. The kava extract and kavalactones accelerated AR protein degradation, while flavokawain B inhibited AR mRNA transcription via decreasing Sp1 expression and the binding of Sp1 to the AR promoter. The kava root extract and flavokawain B reduce tumor growth, AR expression in tumor tissues and levels of serum PSA in the patient-derived PCa xenograft models. These results suggest a potential usefulness of a safe kava product or its active components for prevention and treatment of advanced PCa b

Tran Dang Xuan - One of the best experts on this subject based on the ideXlab platform.

  • Isolation and Purification of Potent Growth Inhibitors from Piper methysticum Root
    Molecules, 2018
    Co-Authors: Tran Dang Xuan, Truong Ngoc Minh, Nguyen Van Quan
    Abstract:

    Piper methysticum (kava) root is known to possess promising weed suppressing activity. The present study was conducted to search for potent plant growth inhibitors from the root of this medicinal pepper plant. The ethyl acetate (EtOAc) extract exhibited the strongest reduction on growth of Raphanus sativus (radish) (IC50 shoot and root growth = 172.00 and 51.31 µg/mL respectively) among solvent extracts. From this active extract, nine potent growth inhibitors involved in the inhibitory activities of P. methysticum root were isolated, purified and characterized by column chromatography (CC), gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). The six fractions purified by CC included two flavanones: 5-hydroxy-4′,7-dimethoxyflavanone (C1) and 5,7-dihydroxy-4′-methoxy-6,8-dimethylflavanone (matteucinol, C2) and six kavalactones: 5,6-dehydro-kavain (C3), a mixture of kavain and yagonin (C4), yagonin (C5) and dihydro-5,6-dehydrokavain, 7,8-dihydrokavain, dihydroMethysticin and Methysticin (C6). The amounts of 5-hydroxy-4′,7-dimethoxyflavanone, matteucinol, 5,6-dehydrokavain and yangonin were 0.76, 2.50, 2.75 and 2.09 mg/g dry weight (DW), respectively. The two flavanones C1 and C2 exhibited the strongest inhibition on shoot elongation (IC50 = 120.22 and 248.03 µg/mL, respectively), whilst the two kavalactone mixtures C4 and C6 showed the highest suppression on root growth of R. sativus (IC50 = 7.70 and 15.67 µg/mL, respectively). This study was the first to report the purification and inhibitory activities of the two flavanones 5-hydroxy-4′,7-dimethoxyflavanone and matteucinol in P. methysticum root. The isolated constituents from P. methysticum root including the flavanones C1 and C2 and the mixtures C4 and C6 may possess distinct modes of action on plant growth. Findings of this study highlighted that the combinations of hexane-ethyl acetate by 9:1 and 8:2 ratios successfully purified flavanones and kavalactones in P. methysticum root.

  • Isolation and Purification of Potent Growth Inhibitors from Piper methysticum Root
    MDPI AG, 2018
    Co-Authors: Truong Mai Van, Tran Dang Xuan, Truong Ngoc Minh, Nguyen Van Quan
    Abstract:

    Piper methysticum (kava) root is known to possess promising weed suppressing activity. The present study was conducted to search for potent plant growth inhibitors from the root of this medicinal pepper plant. The ethyl acetate (EtOAc) extract exhibited the strongest reduction on growth of Raphanus sativus (radish) (IC50 shoot and root growth = 172.00 and 51.31 µg/mL respectively) among solvent extracts. From this active extract, nine potent growth inhibitors involved in the inhibitory activities of P. methysticum root were isolated, purified and characterized by column chromatography (CC), gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). The six fractions purified by CC included two flavanones: 5-hydroxy-4′,7-dimethoxyflavanone (C1) and 5,7-dihydroxy-4′-methoxy-6,8-dimethylflavanone (matteucinol, C2) and six kavalactones: 5,6-dehydro-kavain (C3), a mixture of kavain and yagonin (C4), yagonin (C5) and dihydro-5,6-dehydrokavain, 7,8-dihydrokavain, dihydroMethysticin and Methysticin (C6). The amounts of 5-hydroxy-4′,7-dimethoxyflavanone, matteucinol, 5,6-dehydrokavain and yangonin were 0.76, 2.50, 2.75 and 2.09 mg/g dry weight (DW), respectively. The two flavanones C1 and C2 exhibited the strongest inhibition on shoot elongation (IC50 = 120.22 and 248.03 µg/mL, respectively), whilst the two kavalactone mixtures C4 and C6 showed the highest suppression on root growth of R. sativus (IC50 = 7.70 and 15.67 µg/mL, respectively). This study was the first to report the purification and inhibitory activities of the two flavanones 5-hydroxy-4′,7-dimethoxyflavanone and matteucinol in P. methysticum root. The isolated constituents from P. methysticum root including the flavanones C1 and C2 and the mixtures C4 and C6 may possess distinct modes of action on plant growth. Findings of this study highlighted that the combinations of hexane-ethyl acetate by 9:1 and 8:2 ratios successfully purified flavanones and kavalactones in P. methysticum root

  • Efficacy of extracting solvents to chemical components of kava (Piper methysticum) roots
    Journal of Natural Medicines, 2007
    Co-Authors: Tran Dang Xuan, Ao Chang Wei, Abdelnaser Abdelghany Elzaawely, Tran Dang Khanh
    Abstract:

    The chemical composition of kava ( Piper methysticum ) lactones and various phytochemicals obtained following the sonication of ground kava roots extracted in the solvents hexane, chloroform, acetone, ethanol, methanol and water, respectively, was analyzed. Eighteen kava lactones, cinnamic acid bornyl ester and 5,7-dimethoxy-flavanone, known to be present in kava roots, were identified, and seven compounds, including 2,5,8-trimethyl-1-naphthol, 5-methyl-1-phenylhexen-3-yn-5-ol, 8,11-octadecadienoic acid-methyl ester, 5,7-(OH)_2-4′-one-6,8-dimethylflavanone, pinostrobin chalcone and 7-dimethoxyflavanone-5-hydroxy-4′, were identified for the first time. Glutathione (26.3 mg/g) was found in the water extract. Dihydro-5,6-dehydrokavain (DDK) was present at a higher level than Methysticin and desmethoxyyagonin, indicating that DDK is also a major constituent of kava roots. Acetone was the most effective solvent in terms of maximum yield and types of kava lactones isolated, followed by water and chloroform, whereas hexane, methanol, and ethanol were less effective as solvents. Total phenolic and antioxidant activity varied among the extracting solvents, with acetone and chloroform producing the highest effects, followed by water, while methanol, ethanol and hexane were less effective.

  • Herbicidal and fungicidal activities of lactones in Kava (Piper methysticum)
    Journal of agricultural and food chemistry, 2006
    Co-Authors: Tran Dang Xuan, Masakazu Fukuta, Abdelnaser A. Elzaawely, Shinkichi Tawata
    Abstract:

    This is the first report showing that kava lactones are plant and plant fungus growth inhibitors. Aqueous extract of kava roots showed high allelopathic potential and strongly suppressed germination and growth of lettuce, radish, barnyardgrass, and monochoria. Nine kava lactones were detected using GC-MS including desmethoxyyagonin, kavain, 7,8-dihydrokavain, hydroxykavain, yagonin, 5,6,7,8-tetrahydroxyyagonin, Methysticin, dihydroMethysticin, and 11-hydroxy-12-methoxydihydrokavain. Quantities of desmethoxyyagonin, kavain, 7,8-dihydrokavain, yagonin, Methysticin, and dihydroMethysticin detected were 4.3, 6.9, 18.6, 5.7, 1.4, and 5.4 mg/g of dry weight, respectively. These six major lactones in kava roots showed great herbicidal and antifungal activities. Growth of lettuce and barnyardgrass were significantly inhibited at 1-10 ppm, and four plant fungi including Colletotrichum gloeosporides, Fusarium solani, Fusarium oxysporum, and Trichoderma viride were significantly inhibited at 10-50 ppm. The biological activities of kava lactones were characterized by different double-bond linkage patterns in positions 5,6 and 7,8. The findings of this study suggest that kava lactones may be useful for the development of bioactive herbicides and fungicides.