Abstract

• This paper focused on the health aspects of flavonoids for humans. Among natural compounds, present in everyday diet, flavonoids have shown beneficial effects in prevention of cardiovascular diseases which can be attributed, at least partially to the described antiaggregatory activity i.e. antiplatelet effects of flavonoids. The rhizomes of black ginger were collected from Lashio Township, Northern Shan State and identified by authorized botanist at Botany Department, University of Yangon. Preliminary phytochemical tests were carried out by test tube methods. According to the results, it was found that -amino acids, flavonoids, glycosides, organic acids, phenolic compounds, starch and terpenoids were found to be present. However, alkaloids, carbohydrates, cyanogenic glycosides, reducing sugars and tannins were not detected. 1.78% of PE, 1.92 % EtOAc, 2.50 % EtOH, 2.87 % MeOH and 4.30 % H2O crude extracts were prepared by successive Soxhlet extraction method. Silica gel column chromatographic separation of pet-ether extract from rhizomes of black ginger yielded 0.057% of 5-hydroxy -3,7-dimethoxy flavone (m.pt = 149-150 ºC, yellow needles) and 0.035% of 5-hydroxy-3,7,4'-trimethoxy flavone (m.pt = 144- 146 ºC, yellow needles). The isolated compounds were firstly characterized by their physicochemical properties such as Rf values, melting points, solubilities and some colour tests. The isolated compounds were also identified by using modern spectroscopic techniques such as UV-visible, FT-IR, 1HNMR, 13CNMR and 2DNMR spectroscopy. Black ginger contains polymethoxy flavones which are flavonoids that exhibit various bioactivities. Among these, in vitro aggregatory activity such as platelet-agglutination, platelet-aggregation and clot retraction were investigated by using Ackroyd's method. It was observed that the isolated compounds possessed antiaggregatory activity.