ABSTRACT
This present review provides information on the antihyperglycemic effect of the plants belonging to the genus Ocimum. The species of this genus which mostly show significant antihyperglycemic effects are Ocimum tenuiflorum L., Ocimum basilicum L., Ocimum gratissimum L. and Ocimum canum L. The results were shown in both in vitro and in vivo studies. The anti-hyperglycemic activities of different extracts from all these species are reported here. Aqueous extracts are common to show a satisfactory result for all the species. The results for ethanol, methanol, ethyl-acetate, petroleum ether extracts, chloroform and hexane fraction of ethanol extract are also presented here. Some of the results showed a better effect than the standard medicine. Eugenol is the most important bioactive compound among all the components for reducing blood glucose level. Other components include polyphenols, caffeic acid, p-coumaric acid compound and chichoric acid, which are reportedly found in these species. There are fewer studies performed to identify the phytochemical components which are responsible for these plants blood glucose, serum glucose and plasma glucose lowering effect. This review presents the studies which have been done lately to establish the antihyperglycemic effects of these plants with a view to identify the core components responsible for this activity in near future.
ABSTRACT
Objective To investigate the antidiabetic activity of Ocimum tenuiflorum L. (O. tenuiflorum) leaves used in the traditional medicine management of diabetes in Malaysia. Methods O. tenuiflorum leaves were extracted sequentially with hexane, chloroform, ethyl acetate, methanol, and water. The extracts were evaluated in terms of antidiabetic activity by using acute, subcutaneous glucose tolerance, and sub-chronic tests in streptozotocin-induced diabetic rats. The extracts were also subjected to phytochemical analyses. Results With an acute dose (1 g/kg), the methanol extracts showed significant reduction (31%) in fasting blood glucose (FBG) of the streptozotocin-induced diabetic rats. The FBG-decreasing effect of ethyl acetate extract was more rapid than that of the other extracts; the decreasing rates were 20% after 2 h, 21% after 3 h, and 8% after 5 and 7 h. After 7 h (31%), the effect of methanol extract on FBG was significantly lower than that of metformin. In the subcutaneous glucose tolerance test, only methanol and hexane extracts showed the similarity of metformin in diabetic rats. After 14 days, the effects of these extracts were similar to those of metformin (63.33%). The total flavonoid and phenolic contents of extracts decreased as the polarity of the extraction solvent increased. Conclusions The results obtained provide support for a possible use of O. tenuiflorum leaves in managing hyperglycemia and preventing the complications associated with it in type 2 diabetic.