Simultaneous identification and quantitation of 11 flavonoid constituents in Kaempferia parviflora by gas chromatography.

Kaempferia parviflora (Krachaidum; KD) is a Thai herb, the rhizomes of which have been used in folk medicine and ritual ceremonies. The increasing use of KD has led to concerns regarding the variation of quality, potency and efficacy of KD products. A gas chromatographic method was developed and validated using 11 flavonoids that had been fully characterized as reference. Limits of detection ranged from a low of 0.1 ppm to a high of 1.0 ppm. The limits of quantitation were a low of 0.5 ppm (5-hydroxy-3,7-dimethoxyflavone) to a high of 3.0 ppm (5,7,4'-trimethoxyflavone and 5,7,3',4'-tetramethoxyflavone). Precision of intra- and inter-day analyses gave a RSD range of 3.02-8.25 and 2.84-12.37, respectively. The diversity of flavonoid content and their distribution profiles in KD samples from 12 different origins was investigated using the validated method. Total flavonoid content in these samples ranged from 23.86 to 60.98 mg/g. Two of the compounds, 5,7-dimethoxyflavone and 5,7,4'-trimethoxyflavone, emerged as major constituents. Samples contained as much as 21.68 and 9.88 mg/g, respectively. Two distinct patterns of the distribution of the flavonoids, as characterized by the ratio of these two compounds in the KD rhizome samples, were observed. This method is expected to be useful in the quantitative and qualitative analyses of the flavonoid content of KD samples and as a quality control assessment of KD raw materials and products.

Coumarins and carbazoles with antiplasmodial activity from Clausena harmandiana.

Activity guided fractionation of extracts from Clausena harmandiana have led to the identification of four known compounds, heptaphylline (1), clausine K (2), dentatin (5), and clausarin (6). All these compounds, except clausine K (2), exhibited antiplasmodial activity against Plasmodium falciparum. While the new dimethylated derivative 4, derived from 2, showed no antiplasmodial activity, the monomethylated product 3 (clausine H) exhibited activity comparable to that observed for compounds 1 and 5.

Nimbolide, a constituent of Azadirachta indica, inhibits Plasmodium falciparum in culture.

The terpenoid lactone nimbolide, the structure of which has been unambiguously established, was found to inhibit Plasmodium falciparum in culture with a moderate potency. The EC50 against the parasite line K1 from Thailand was approximately 2.0 microM (0.95 microgram/ml). The EC50 of crude aqueous extract of Azadirachta indica var. siamensis (Sadao tree), was 115 micrograms/ml, and of crude ethanol extract was 5.0 micrograms/ml. Since nimbolide is a major constituent in these extracts, it could account substantially for their inhibitory activity. However, neither the crude extracts nor nimbolide showed any activity in vivo against Plasmodium berghei in the mouse either through ingestion (746 mg aqueous extract, 62.5 mg ethanol extract or 12.5 mg nimbolide/kg/day), or subcutaneous injection (93 mg aqueous extract, 31 mg ethanol extract or 12.5 mg nimbolide/kg/day).