Phytochemical screening and preliminary clinical trials of the aqueous extract mixture of Andrographis paniculata (Burm. f.) Wall. ex Nees and Syzygium polyanthum (Wight.) Walp leaves in metformin treated patients with type 2 diabetes.

Our previous preclinical study showed that the extract mixture (EM) of Andrographis paniculata (Burm. f.) Wall. ex Nees (AP) and Syzygium polyanthum (Wight.) Walp (SP) leaves had antidiabetic effects and were beneficial on alloxan-induced diabetic rats.The objectives of this study were to: 1) identify the phytochemical compounds present in aqueous extract of AP and SP and 2) examine the benefits of the EM of AP and SP leaves in lowering blood glucose in the presence of standard antidiabetic treatment using metformin in type 2 diabetic patients in Indonesian Traditional Medicine Polyclinic of Dr. Soetomo General Hospital in Surabaya.Phytochemical analysis of aqueous leaf extract of AP and SP was performed using standard chemical tests, TLC, and GC-MS. Furthermore, a total of 54 subjects with T2DM participated in this study and were randomly assigned to either the intervention group supplemented with the extract mixture of AP and SP at a dose 900 mg/day for 8 weeks, or the control group which received placebo tablets in a randomized placebo-controlled double-blinded parallel clinical trial. Both groups received metformin at dose 1000 mg/day. Body weight, blood pressure, fasting blood glucose, postprandial glucose, haemoglobin A1c, triglycerides, total cholesterol, low density lipoprotein, high density lipoprotein, and markers of liver and kidney damage were measured.The results of phytochemical analysis showed that the glycosides, terpenoids, alkaloids, flavonoids, saponins, and tannins were found to be present in the extract mixture. GC-MS analyses of AP and SP showed the presence of 19 and 12 peaks, respectively. Methyl ester of 9-octadecenoic and eicosanoic acid were determined as the main constituents of both species. Moreover, the results of clinical study suggested that the extract mixture improved the decrease of fasting blood glucose and postprandial glucose, significantly lowered body mass index compared with the control group. The EM appeared beneficial for SGPT values and uric acid levels.Overall, the results of this study suggested the potential beneficial effects of the extract mixture for use as complementary medicine alongside conventional treatment of metformin. The extract mixture contained many highly potent compounds for treating T2DM and preventing short- and long-term risk complications of diabetes.