Phytomedicine Plus (May 2021)
Response surface methodology based extraction optimization to improve pharmacological properties and 1H NMR based metabolite profiling of Azadirachta indica
Abstract
Background: Many studies shed light on the therapeutic importance of Azadirachta indica leaves extract as a source of drugs and neutracuticles for treatment of different diseases including diabetes mellitus. The extraction of these bioactive phytochemicals is optimized according to different pharmacological applications of extract. Study design: The current study was performed to optimize the extraction from leaves of Azadirachta indica. The temperature, extraction time, solid to liquid ratio, ethanol concentration and ultrasonication frequency were optimized to improve extract yield with improved antioxidant and α-glucosidase inhibitory properties. Methods: Utrasonication assisted extraction from Azadirachta indica leaves was optimized using Response Surface Methodology. Sets of extraction conditions that gave optimum yield, antioxidant activity and α-glucosidase inhibition were determined through statistical analysis. The phytochemicals present in extract were identified by 1H NMR and docked with homology modelled α-glucosidase structure to get and insight of enzyme-phytochemicals interaction. Results: The maximum extract yield and α-glucosidase inhibition were observed when plant sample was extracted with 60% ethanol (15% solid-liquid ratio), and ultrasonication was done at 35 °C for 75 min having frequency of 30 KHz. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging observed the same extraction strategy except the time duration for ultasonication which was 52.5 min. The 1H NMR based metabolite profiling revealed the identification of 2α,4α,dihydroxy-pregn-5-en-(6-one-3α-O-D-glu-copyranoside, ferruginol, azadirachtin A, meliatetraolenone, odoratone, 7α‑hydroxy-15-β‑hydroxy-7′15,dioxonimbin, zeeshanol, nimbinene, epoxyazadiradione, azadirachtin B, 17-(5‑methoxy-2-oxo-furan-3-yl)-28-deoxonimbolide, epicatechin, 2-oxo-3-deacetyl salanin (nimbolide derivative), nimonol, nimbic acid B, 3‑methoxy-cumerine 6–0-(1,4) triglycoside, 17‑hydroxy-sandaracopimar-8,15-en-11-one(diterpene), and 23-O-methylnimocinolide. The molecular docking studies provided a deep insight on molecular interactions which might be useful for antidiabetic drug development. Conclusion: Azadirachta indica leaves extract contain various bioactive compounds and can be considered as a source of α-glucosidase inhibitors hence, it may also be used for the development of functional foods.
