Health-Promoting Lipids from Purslane (Portulaca oleracea L.): Isolation, Characterization, Quantification and In Vivo Assay of Angiogenic Activity

摘要

Phytosterols, alpha -tocopherol and squalene were isolated from purslane (Portulaca oleracea L.) using a combination of solvent extraction, saponification and thin layer chromatography, and were characterized using standard chemical tests and ultraviolet and Fourier transform infrared spectroscopy. The levels of these lipids per 100 g fresh weight were quantified as follows: 6.52+or-0.44 mg phytosterols, 9.05+or-0.04 mg alpha -tocopherol and 115.0+or-2.0 micro g squalene. Argentation thin layer chromatography further resolved the phytosterol isolate into beta -sitosterol, stigmasterol and campesterol, the identities of which were established through melting point determination coupled with ultraviolet and Fourier transform infrared spectroscopy. Furthermore, gas chromatographic analysis of purslane oil revealed the presence of the omega-3 fatty acids alpha -linolenic acid and docosahexaenoic acid at 17.00+or-0.33% and 5.08+or-0.49%, respectively, of purslane oil. A new semi-quantitative in vivo duck embryo chorioallantoic membrane (CAM) assay for angiogenesis was described in this study including a scoring system with a scale of -3 to +3, with -3 as the score for complete loss of blood capillaries. Purslane oil and its saponifiable and unsaponifiable fractions exhibited scores of -1 to -2.7 when applied to CAM at 150-300 micro g. Their anti-angiogenic activity can be attributed to the presence of phytosterols, alpha -tocopherol, squalene and omega-3 fatty acids. This study revealed the potential use of purslane in modulating angiogenesis.