Reference

Changes in chemical composition of "yaqona" (Piper methysticum) with time

Changes in chemical composition of "yaqona" (Piper methysticum) with time. Duve, R. N.; Prasad, J. (Res. Div., Minist. Primary Ind., Fiji). Fiji Agric. J., 45(2), 45-50 (English) 1983. CODEN: FJAJAB. ISSN: 0015-0886. DOCUMENT TYPE: Journal CA Section: 17 (Food and Feed Chemistry) Storage of dried, powd. roots and basal stems of yaqona (P. methysticum) in screw capped glass bottles at room temp. has shown that 55.0, 33.1, and 26.2% of the major active constituents in roots and 48.2, 50.6, and 24.0% in basal stems deteriorate after 39, 36, and 22 mo of storage time, resp. The overall stability of the major constituents increased in the order of constituents: dihydrokawain [587-63-3], kawain [500-64-1], dehydrokawain [15345-89-8], tetrahydroyangonin [3328-59-4], dihydromethysticin [19902-91-1], yangonin [500-62-9], and methysticin [495-85-2]. After 39 mo of storage, 93.9% of dihydrokawain, 81.6% of kawain, 72.4% of dehydrokawain, 54.9% of tetrahydroyangonin, 25.8% of dihydromethysticin, 32.1% of yangonin, and 29.5% of methysticin had deteriorated in the powd. root samples. In the powd. basal stems 93.0% of dihydrokawain, 80.6% of kawain, 60.7% of dehydrokawain, 43.2% of tetrahydroyangonin, 16.9% of dehydromethysticin, 23.0% of yangonin, and 15.7% of methysticin had deteriorated after 39 mo of storage.

High-performance liquid chromatography of kava lactones from Piper methysticum

High-performance liquid chromatography of kava lactones from Piper methysticum. Smith, Roger M.; Thakrar, H.; Arowolo, T. A.; Shafi, A. A. (Dep. Chem., Loughborough Univ. Technol., Loughborough/Leics. LE11 3TU, UK). J. Chromatogr., 283, 303-8 (English) 1984. CODEN: JOCRAM. ISSN: 0021-9673. DOCUMENT TYPE: Journal CA Section: 64 (Pharmaceutical Analysis) Section cross-reference(s): 11 The kava lactones from different plant parts of P. methysticum were nearly completely sepd. by chromatog. on a column of Alox T with 1% MeCN in CH2Cl2 and aminoazobenzene as internal std. Yangonin (I) [500-62-9] and kawain [500-64-1] were not sepd. but they could be discriminated by the absorbance peaks at 254 and 355 nm. Kawain was the major lactone of the root, dihydromethysticin [19902-91-1] was the major compd. in the stem, and dihydrokawain [587-63-3] levels were highest in the leaf (34.5, 59.6, and 69.8%, resp.). Photoisomerization of I occurred in the mobile phase during sample prepn. The cis-yangonin [89272-44-6] formed could be sepd.In this experiment, several chemicals are used like 500-62-9 and 500-64-1 from I by chromatog. on an ODS-Hypersil column with MeOH-H2O (). In daylight, equil. of the isomers was reached in about 90 min, with a cis/trans ratio of . .