Hydrocotyle umbellata L.; a natural source of bioactives to mitigate diabetes mellitus and its complications.

Metabolomics study of Hydrocotyle umbellata L. revealed the richness of its aerial parts in phenolics primarily; quercetin and its glycoside derivatives, which are well-reported to exert antidiabetic activity owing to their powerful antioxidant capacity. Hence, the antioxidant and antidiabetic potentials of the quercetin standardized ethanolic extract of H. umbellata aerial parts were investigated. The antioxidant activity was examined by using in-vitro 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay, while the antidiabetic activity was examined by using in-vitro α-glucosidase inhibitory assay and further confirmed by in-vivo experiments using streptozotocin-induced diabetes in rat model. Interestingly, the standardized ethanolic extract showed significant in-vitro antioxidant activity, and effectively inhibited Saccharomyces cerevisiae α-glucosidase enzyme activity. Moreover, it significantly reduced fasting blood glucose, triglycerides, and cholesterol levels. Thus, H. umbellata is a potential natural candidate to attenuate diabetes mellitus and its altered lipid profile complications, which could be attributed to its quercetin and quercetin glycosides content.

In-vivo Anti-inflammatory Activity of Hydrocotyle umbellata L. aerial parts and Isolation of the Main Phytochemicals.

Hydrocotyle umbellata L. (Family Araliaceae) populary known as Acaricoba, is indicated in folk medicine for treatment of several inflammatory disorders. The goal of the present study is to evaluate the anti-inflammatory activity of the defatted ethanolic extract (DEE) of the aerial parts using carrageenan-induced rat paw oedema method. The levels of the pro-inflammatory cytokine interleukin-6 (IL-6) and the inflammatory mediator prostaglandin E2 (PGE2) were assessed using ELISA. The DEE at dose level 100 mg/kg showed significant decrease in oedema volume after 2 and 3 h, equivalent to 70.75% and 95.92% of the activity of the standard anti-inflammatory indomethacin, respectively. DEE significantly decreased the concentrations of the excessively produced IL-6 and PGE2 (24 ± 2.1 and 2374 ± 87 pg/mL compared to 16 ± 2 and 2419 ± 95 pg/mL induced by indomethacin). Chemical investigation was carried out to isolate and identify the bioactive compounds that might be responsible for this activity. The total phenolic (79.28 ± 0.1 mg) and total flavonoid (57.99 ± 0.1 mg) contents of the DEE were quantified spectrophotometricaly and expressed as gallic acid and rutin equivalents/g dry weight, respectively. The DEE was subjected to further fractionation using solvents of increasing polarities. Purification of the ethyl acetate fraction using different chromatographic techniques led to the isolation of five compounds, which were identified through 1D and 2D and UV/Vis spectral data. The five compounds were: quercetin, avicularin, quercitrin, hyperoside, and neochlorogenic acid. Several biological studies confirmed the important role of caffeoyl quinic acid and quercetin derivatives as anti-inflammatory bioactive compounds.

Polyhydroxy Sterols Isolated from the Red Sea Soft Coral. Lobophytum crassum and their Cytotoxic Activity.

One new (1) together with four known sterols (2 - 5) and a sesquiterpene (6) were isolated from a polar extract of the Red Sea soft coral Lobophytum crassum. The compounds were identified as 24-methylenecholest-5-ene-lα,3ß,1lα-triol 1-acetate (1), 24-methylenecholest-5-ene-la,3ß,llα-triol (2), 24- methylenecholest-5-ene-3ß-ol (3), 24-methylenecholestane-la,3ß,5α,6ß,I la-pentol (4), 24-methylenecholestane-3ß,5α,6ß-triol (5) and alismoxide (6) based on extensive NMR analysis. The cytotoxicity of compounds 1 - 6 was evaluated in vitro using three human cancer cell lines viz., HepG2, Hep-2 and HCT-I 16. Compound 1 showed selective cytotoxic activity against HepG2, while 3 exhibited cytotoxicity against all tested cell lines.

Metabolites profiling of Chrysanthemum pacificum Nakai parts using UPLC-PDA-MS coupled to chemometrics.

Methanol-soluble constituents from the flowers, non-flowering aerial parts and roots of Chrysanthemum pacificum Nakai were analysed via high resolution UPLC-PDA-qTOF-MS followed by chemometrics. Forty-seven chromatographic peaks belonging to various metabolite classes were detected. Most metabolite classes showed qualitative and quantitative differences across parts, with luteolin conjugates being mostly enriched in flowers whereas non-flowering aerial parts contained mostly quercetin and methoxylated flavone conjugates. Root sample ranked the lowest for all flavones and dicaffeoylquinic acids. In contrast, 1,5-di-caffeoylquinic acid levels were found at high levels in flowers and aerial parts reaching 3145 and 1390 µg/g, respectively, suggesting that C. pacificum could serve as a natural resource of this well-recognised anti-hepatotoxic phenolic. Principal component analysis was further used for organs classification in an untargeted manner. This study provides the first map of secondary metabolites distribution in C. pacificum Nakai organs.

Bioactive terpenoids from the Red Sea soft coral Sinularia polydactyla.

Chemical investigation of an ethyl acetate soluble fraction of Sinularia polydactyla (Ehrenberg) led to the isolation of three known terpenoides, two of them sterols, 24-methylcholestane-3ß,5α,6ß,25-tetrol 25-monoacetate (1), 24-methylcholestane-5-en-3ß,25-diol (2), in addition to a cembranoid diterpene, durumolide C (3), for the first time. The cytotoxicity and antimicrobial activities of the ethyl acetate extract and the isolated compounds 1-3 were evaluated in vitro. Durumolide C (3) showed selective cytotoxicity against HepG2 (IC50 1.0 µg/mL), whereas 24-methylcholestane-3ß,5α,6ß,25-tetrol 25-monoacetate (1) showed IC50 of 6.1 and 8.2 µg/mL against Hep2 and HCT human cancer cell lines, respectively.

Polyphenolic compounds from flowers of Hibiscus rosa-sinensis Linn. and their inhibitory effect on alkaline phosphatase enzyme activity in vitro.

Graded concentrations (0.1-100 mg/mL reaction mixture) of the methanolic extract of the flowers of Hibiscus rosa-sinensis Linn., its water-soluble fraction as well as compounds isolated from this fraction were tested for their inhibitory effect on alkaline phosphatase enzyme activity in vitro. Both the methanolic extract and its water-soluble fraction showed significant inhibitory effects on the enzyme activity in vitro. On screening the activity of the compounds isolated from the water-soluble fraction, its high inhibitory activity was attributed to the presence of quercetin-7-O-galactoside which showed a high potent inhibition of the enzyme activity reaching 100% at 100 mg/mL reaction mixture. Phytochemical investigations of the water-soluble fraction were also carried out and afforded ten polyphenolic compounds including two new natural compounds, namely kaempferol-7-O-[6'''-O-p-hydroxybenzoyl-beta-D-glucosyl-(1-->6)-beta-D-glucopyranoside] and scutellarein-6-O-alpha-L-rhamnopyranoside-8-C-beta-D-glucopyranoside). The chemical structure of the isolated compounds was elucidated on the basis of chemical and spectral data.