Effects of Solvent-free Microwave Extraction on the Active Substances from Hemp Leaves of Bioactive Compounds and Inhibitions of Enzymes Relevant to Non-communicable Diseases (NCDs)

Abstract

Non-communicable diseases (NCDs) pose a significant public health challenge in Thailand and globally, resulting in economic burdens and side effects from pharmaceutical treatments. To mitigate these issues, the use of plant extracts as preventive measures has gained attention. This research investigated the effects of solvent-free microwave extraction of hemp leaves on bioactive compounds. Hemp leaf extracts were obtained using microwave power settings of 150, 250 and 350 W for durations of 15 and 30 minutes. The study evaluates the antioxidant activity through assays including DPPH, FRAP, metal chelating activity, and hydroxyl radical scavenging, as well as the inhibitory effects on enzymes related to various health conditions, including ACE (hypertension), DPP–IV (type 2 diabetes), α–amylase and α–glucosidase (type 2 diabetes and obesity), and HMG–CoA reductase (hyperlipidemia). The valuable compounds in hemp leaves were extracted using microwave–assisted extraction at 350 W for 15 minutes. This extraction method yielded the highest DPPH, FRAP, and hydroxyl radical scavenging activities, with respective EC₅₀ values of 0.75, 0.39 and 1.16 mg/ml. Furthermore, it exhibited the most potent inhibitory effects on ACE, α–amylase, and α–glucosidase enzymes, with IC₅₀ values of 0.35, 0.14 and 0.23 mg/ml, respectively. Furthermore, the valuable compounds extracted from hemp leaves using microwave–assisted extraction at 250 W for 30 minutes were identified as the most effective in inhibiting DPP–IV (IC₅₀=0.37 mg/ml) and HMG–CoA reductase (IC₅₀=1.18 mg/ml). This study highlights the nutritional potential of hemp leaf extracts as a promising strategy for preventing NCDs.