A single factor experiment design was employed to optimize ultrasonic assisted extraction of Hibiscus cannabinus L. (kenaf) leaves. Ethanol concentration and extraction times (min) were optimized in the study as this extraction parameters were believed to have effect on the recovery of bioactive compounds derived from kenaf leaves extract (KLE). Considering all the results obtained from the experiment, it displayed that the 95 % ethanolic kenaf leaves that went through 3 min extraction was the optimum extraction condition, with significant highest (p < 0.05) of total flavonoid content (TFC) (48.20 ± 0.15 mgCHE/g), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) (33.99 ± 1.58 mgTEAC/g) and 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay (34.23 ± 0.18 mgTEAC/g). TFC was significantly correlated with DPPH and ABTS under the effects of ethanol concentration. The optimized KLE also showed high total phenolic content (TPC), ferric reducing antioxidant power (FRAP), and tyrosinase inhibitory activity. Besides, the optimized KLE were reported to be effective in bactericidal activity against five investigated pathogenic bacteria (Bacillus cereus, Staphylococcus epidermis, Salmonella, Pseudomonas aeruginosa, and Escherichia coli) with the minimum inhibitory concentration (MIC) values of 2.5, 5 and 10 mg/mL.

采用单因素实验设计优化超声波辅助提取木槿大麻L.（红麻）叶子。在研究中优化了乙醇浓度和提取时间 (min)，因为人们认为该提取参数对红麻叶提取物 (KLE) 中生物活性化合物的回收率有影响。综合实验结果，95%乙醇红麻叶提取3分钟是最佳提取条件，总黄酮含量(TFC)显着最高(p < 0.05) (48.20 ± 0.15 mgCHE) /g), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) (33.99 ± 1.58 mgTEAC/g) 和 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) 自由基清除试验（ 34.23±0.18mgTEAC/g)。在乙醇浓度的影响下，TFC 与 DPPH 和 ABTS 显着相关。优化的 KLE 还显示出高总酚含量 (TPC)，铁还原抗氧化能力 (FRAP) 和酪氨酸酶抑制活性。此外，据报道优化的 KLE 对五种研究的病原菌具有有效的杀菌活性。蜡样芽孢杆菌、表皮葡萄球菌、沙门氏菌、铜绿假单胞菌和大肠杆菌）的最低抑菌浓度 (MIC) 值为 2.5、5 和 10 毫克/毫升。