Peer Review #1 of "In vitro anti-diabetic effects and phytochemical profiling of novel varieties of Cinnamomum zeylanicum (L.) extracts (v0.1)"

Abstract

Background: Diabetes mellitus type 2 (DMT2) is a common metabolic disorder in the world. Antidiabetic actions of phytochemicals from various medicinal herbs are considered as an alternative to the drugs used in the management of DMT2 in allopathic medicine due to adverse effects of synthetic drugs. α-amylase and α-glucosidase inhibitory potential and phytochemical profiling were investigated in aqueous extracts of two new Cinnamomum zeylanicum accessions, namely C. zeylanicum Sri Wijaya (SW), C. zeylanicum Sri Gemunu (SG) and commercially available C. zeylanicum (CC). Methods: Microwave Digestion (MD), Pressurized Water Extraction (PWE), Steam Distillation (SD), Solvent Extraction (SE), Decoction Water Extraction (DWE) and Infusion Water Extraction (IWE) methods were used to prepare Cinnamon quill extracts. Total phenolic content (TPC, Folin-Ciocalteu method) and Proanthocyanidin content (PC, vanillin assay), α-amylase and α-glucosidase inhibition of Cinnamon extracts were determined spectrophotometrically. The α-amylase and α-glucosidase inhibition were reported in terms of IC 50 value. The phytochemical profiling was accomplished by GC-MS technique. Results and discussion: Lowest IC 50 values were observed in PWE and DWE of SW. Highest PC and TPC was also observed in PWE and DWE of SW. Pressured water and decoctions are promising methods for the extraction of antidiabetic constituents from Cinnamon. Benzoic acid, Cinnamyl alcohol, Benzyl alcohol, and 4-Allyl-2,6-dimethoxyphenol were identified as major compounds in SW extracts. These compounds are believed to be responsible for strong enzyme inhibitory activity of the extracts. Conclusions: This is the first study to explore the use of pressured and decoctions water to extract antidiabetic phytochemicals from Cinnamon. The extensive metabolite profiling of novel SW and SG extracts and comparison of that with commercially available CC are reported for the first time in this study. The C. zeylanicum, SW accession holds some promise in the management of diabetes.