Investigation of phenolic leaf extract of Heimia myrtifolia (Lythraceae): Pharmacological properties (stimulation of mineralization of SaOS-2 osteosarcoma cells) and identification of polyphenols.

Evaluation of the activity of an aqueous alcoholic extract obtained from the leaves of Heimia myrtifolia (Lythraceae) by determining its stimulating effect on two human osteoblastic cell lines HOS58 and SaOS-2 indicated its potential for use in the prevention and treatment of osteoporosis. In addition, the extract was found to significantly increase the mineralization of cultivated human bone cell SaOS-2, in which a strong dose-dependent increase was observed. A phytochemical investigation of the extract also confirmed that H. myrtifolia is capable of synthesizing and accumulating appreciable amounts of several phenolics, thus leading to the isolation and characterization of sixteen of these constituents. Identified among these isolates were a new natural product, 1,6-di-O-dehydrotrigalloyl-ß-D-(4)C(1)-glucopyranose, and a rare natural product (this marks its second report), 5,7,4'-trihydroxy-3-methoxyflavanone (dihydrokaempferol-3-O-methyl ether). Structures of these isolates were fully elucidated on the basis of conventional methods of analysis and confirmed by ESI/MS and (1)H and (13)C-NMR analysis.

Potential antioxidant phenolic metabolites from doum palm leaves

The antioxidant activity of the aqueous ethanolic extract of doum leaves, Hyphaene thebaica L.(Palmae) was studied. Data obtained showed that the extract can inhibit reactive oxygen species attack on salicylic acid (IC50 = 1602 µg/ml) in a dose dependant manner using xanthine/hypoxanthine oxidase assay. Four major flavonoidal compounds were identified by LC/SEI as; Quercetin glucoside, Kaempferol rhamnoglucoside and Dimethyoxyquercetin rhamnoglucoside. While, further in-depth phytochemical investigation of this extract lead to the isolation and identification of fourteen compounds; their structures were elucidated based upon the interpretation of their spectral data (UV, 1H, 13C NMR and ESI/MS) as; 8-C--D-glucopyranosyl-5, 7, 4`-trihydroxyflavone (vitexin) 1, 6-C--D-glucopyranosyl-5, 7, 4`-trihydroxyflavone (iso-vitexin) 2, quercetin 3-O--4C1-D-glucopyranoside 3, gallic acid 4, quercetin 7-O--4C1-D-glucoside 5, luteolin 7-O--4C1-D-glucoside 6, tricin 5 O--4C1-D-glucoside 7, 7, 3` dimethoxy quercetin 3-O-[6''-O--L-rhamnopyranosyl]--D-gluco-pyranoside (Rhamnazin 3-O-rutinoside) 8 kaempferol-3-O-[6''-O--L-rhamnopyranosyl]--D-glucopyranoside (nicotiflorin) 9, apigenin 10, luteolin 11, tricin 12, quercetin 13 and kaempferol 14

Hematological studies on black cumin oil from the seeds of Nigella sativa L.

The methanol soluble portion of black cumin oil, which is prepared by compression of seeds of Nigella sativa L., showed inhibitory effects on arachidonic acid (AA)-induced platelet aggregation and blood coagulation. By bioactive assay of AA-induced platelet aggregation, the methanol soluble part was purified to isolate a new compound 2-(2-methoxypropyl)-5-methyl-1,4-benzenediol (1) and two known compounds, thymol (2), carvacrol (3), having very strong inhibitory activity. Further, we then examined the isolated compounds (1-3) and eight related compounds by the screening test for AA-induced platelet aggregation. Compounds possessing aromatic hydroxyl and acetoxyl group had more potent activity than aspirin, which is well known as a remedy for thrombosis.

Flavonoids from Cleome droserifolia suppress NO production in activated macrophages in vitro.

The effect of an Egyptian medicinal plant, Cleome droserifolia (Forssk.) Del. on nitric oxide (NO) production in bacillus Calmette-Guérin-induced mouse peritoneal macrophages activated by lipopolysaccharide was investigated in vitro. The methanol extract of C. droserifolia reduced the NO production, and two flavonoids were isolated as the active components. The new one was determined to be 5,4'-dihydroxy-6,7,8,3',5'-pentamethoxyflavone (1) and the other was identified as 5,4'-dihydroxy-6,7,8,3'-tetramethoxyflavone (8-methoxycirsilineol; 2). Compound 1 concentration-dependently suppressed the NO production and was effective at a non-toxic concentration (12.5 micrograms/ml). The suppressive activity of 2 was weaker than that of 1.

Acetylated flavonol triglycosides from Ammi majus L.

Two new acetylated flavonol triglycosides: kaempferol and isorhamnetin 3-O-[2"-(4"'-acetylrhamnosyl)-6"-glucosyl] glucosides, were isolated and identified from the aerial parts of Ammi majus L. In addition, three known flavonol glycosides namely; isorhamnetin-3-O-rutinoside, kaempferol-3-O-glucoside and isorhamnetin-3-O-glucoside were detected.