A reversed-phase high-performance liquid chromatographic method is described for the simultaneous determination of rhinacanthin-C, rhinacanthin-D, and rhinacanthin-N in Rhinacanthus nasutus leaves. The method involved the use of a TSK-gel ODS-80Ts column (5 microm, 4.6 x 150 mm i.d.) with the mixture of methanol and 5% aqueous acetic acid (80:20, v/v) as the mobile phase. The parameters of linearity, repeatability, accuracy, and specificity of the method were evaluated. The recovery of the method was 94.3-100.9%, and good linearity (r(2) > or = 0.9999) was obtained for all rhinacanthins. A high degree of specificity as well as repeatability and reproducibility (relative standard deviation values less than 5%) were also achieved. The limit of detection and quantification of all rhinacanthins were 0.75 and 3.0 microg/mL, respectively. The solvents for extraction of rhinacanthins from R. nasutus leaves were examined in order to obtain the leaf extract with high rhinacanthin content. It was found that ethyl acetate was an appropriate solvent for rhinacanthin extraction. Fractionation of the ethyl acetate extract using a basic anion exchange resin (Amberlite IRA-67) eluted with 10% acetic acid in methanol afforded a rhinacanthin-rich extract (HRn). The total content of rhinacanthins was increased from 37.4% w/w to 77.5% w/w. The antifungal activities of HRn against Trichophyton rubrum, T. mentagrophytes, and Microsporum gypseum were also improved.

A simple one-step purification using liquid-liquid extraction for preparing pomegranate peel extract rich in ellagic acid has been demonstrated. The method involved partitioning of the 10% v/v water in methanol extract of pomegranate peel between ethyl acetate and 2% aqueous acetic acid. This method was capable of increasing the ellagic acid content of the extract from 7.06% to 13.63% w/w. Moreover, the antioxidant activity of the extract evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay was also increased (ED(50) from 38.21 to 14.91 micro/mL). Stability evaluations of the ellagic acid-rich pomegranate peel extract in several conditions through a period of four months found that the extracts were stable either kept under light or protected from light. The extracts were also stable under 4 degrees +/- 2 degrees C, 30 degrees +/- 2 degrees C and accelerated conditions at 45 degrees C with 75% relative humidity. However, study on the effect of pH on stability of the extract in the form of solution revealed that the extract was not stable in all tested pH (5.5, 7 and 8). These results indicated that the ellagic acid-rich pomegranate peel extract was stable when it was kept as dried powder, but it was not stable in any aqueous solution.

On the basis of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay-guided purification, ellagic acid was isolated from the methanol extract of pomegranate fruit peel by liquid-liquid extraction and chromatographic techniques. A reversed-phase high-performance liquid chromatography was described for determination of ellagic acid in pomegranate fruit peel extract. The method involved the use of a TSK-gel ODS-80Tm column with a mixture of 2% aqueous acetic acid and methanol (gradient elution mode: 0-15 min, 40-60% v/v methanol and 15-20 min, 60% v/v methanol) as the mobile phase and detection at 254 nm. The parameters of linearity, repeatability, reproducibility, accuracy, and specificity of the method were evaluated. The recovery of the method was 98.5% and linearity (r(2) > 0.9995) was obtained for ellagic acid. A high degree of specificity as well as repeatability and reproducibility (relative standard deviation values less than 5%) were also achieved. The limits of detection and quantification were 1.00 and 2.50 microg/mL, respectively. The solvent for extraction of ellagic acid from pomegranate fruit peel was examined in order to maximize the ellagic acid content of the extract. A solution of 10% v/v water in methanol was capable of increasing the ellagic acid content in the extract up to 7.66% w/w. The ellagic acid content and antioxidant activity of the ethyl acetate fraction separated from the crude extract using water and ethyl acetate partition was higher than that of the crude extract.

Mangosteen, Garcinia mangostana L., is known as the "Queen of fruits" and can be cultivated in the tropical rainforest such as Malaysia, Indonesia, and Thailand. Compounds isolated from the fruit peel of mangosteen contain abundant xanthones (especially alpha-mangostin). It has been used as traditional medicine such as anti-inflammatory and antibacterial and is popularly applied to cosmetic and pharmaceutical products. However, there is little information for quality and quantity determination of alpha-mangostin in mangosteen. Thus, the aim of this study was to set up a validated and stability-indicated isocratic reverse-phase high-performance liquid chromatographic (HPLC) method for quality control and quantity determination of a-mangostin from mangosteen peel extract. The assay was fully validated and shown to be linear (r(2) > 0.999), sensitive (LOD = 0.02 microg/mL and LOQ = 0.08 microg/mL), accurate (intra-day was between 98.1-100.8%, inter-day was between 90.0-101.3%), precise (intra-day variation < or = 1.8%, inter-day variation < or = 4.3%), specific, and with good recovery. Total analysis was approximately 8 min. The finalized method is also a stability-indicating assay. The present method should be useful for analytical research and for routine quality control analysis of alpha-mangostin in mangosteen peel extract and products of mangosteen.

A new megastigmane diglycoside, inamoside 6'-O-L-alpha-arabinofuranoside (cuneatoside), was isolated from the leaves and branches of Erythroxylum cuneatum together with seven known compounds, (+)-catechin, quercetin 3-O-alpha-L-rhamnoside, apocynol B, (6S,9R)-roseoside, vomifoliol 9-O-alpha-L-arabinofuranosyl (1-->6)-beta-D-glucopyranoside, inamoside, and citroside A The structural elucidations were based on analyses of physical and spectroscopic data.