Evaluation of the Enzyme Inhibitory and Antioxidant Activities of Entada spiralis Stem Bark and Isolation of the Active Constituents
Authors
Fatimah Roheem
Department of Pharmaceutical Chemistry, International Islamic University Malaysia, Bandar Indera Mahkota, 25200 Kuantan, Pahang D.M., Malaysia; [email protected] (F.O.R.); [email protected] (Q.U.A.)
Siti Soad
Department of Pharmaceutical Chemistry, International Islamic University Malaysia, Bandar Indera Mahkota, 25200 Kuantan, Pahang D.M., Malaysia; [email protected] (F.O.R.); [email protected] (Q.U.A.)
Qamar Ahmed
Department of Pharmaceutical Chemistry, International Islamic University Malaysia, Bandar Indera Mahkota, 25200 Kuantan, Pahang D.M., Malaysia; [email protected] (F.O.R.); [email protected] (Q.U.A.)
Syed Shah
Atta-ur-Rahman Institute for Natural Products Discovery (AuRIns), Universiti Teknologi MARA, Bandar Puncak Alam, 42300 Selangor Darul Ehsan, Malaysia; [email protected]
Jalifah Latip
School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bandar Baru Bangi, Selangor, Malaysia; [email protected]
Zainul Zakaria
Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
Digestive enzymes and free radical inhibitors are used to prevent complications resulting from diabetes. Entada spiralis (family Leguminosae), which is a well-known medicinal plant in herbal medicine due to its various traditional and medicinal applications, was studied. Crude extracts were successively obtained from the stem bark using petroleum ether, chloroform and methanol as extracting solvents. The antioxidant activity of all the extracts, fractions and isolated compounds were estimated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene and 2,2′-azinobis(-3-ethylbenzothiazine-6-sulfonic acid) (ABTS) assays, while digestive enzymes inhibitory activity was assessed using α-amylase and α-glucosidase inhibitory methods. Structure elucidation of pure compounds was achieved through different spectroscopic analysis methods. Fractionation and purification of the most active methanol extract resulted in the isolation of a ferulic ester namely; (e)-hexyl 3-(4-hydroxy-3-methoxyphenyl) acrylate (FEQ-2) together with five known phenolic constituents, identified as kaempferol (FEQ-3), 5,4′-dihydroxy-3,7,3′-trimethoxyflavone (FEQ-2), gallic acid (FEQ-5), (+)-catechin (FEQ-7) and (−)-epicatechin (FEQ-8). FEQ-5 exhibited the strongest antioxidant and enzyme inhibitory activities followed by FEQ-3 and FEQ-4. FEQ-2 also displayed potent free radical scavenging activity with IC50 values of 13.79 ± 2.13 (DPPH) and 4.69 ± 1.25 (ABTS) µg/mL, respectively. All other compounds were found active either against free radicals or digestive enzymes.
Keywords: Entada spiralis; 2,2-diphenyl-1-picrylhydrazyl assay; β-carotene assay; 2,2′-azinobis(-3-ethylbenzothiazine-6-sulfonic acid) assay; α-amylase; α-glucosidase; active principles
Author Biographies
Syed Shah, Atta-ur-Rahman Institute for Natural Products Discovery (AuRIns), Universiti Teknologi MARA, Bandar Puncak Alam, 42300 Selangor Darul Ehsan, Malaysia; [email protected]
Faculty of Pharmacy, Universiti Teknologi MARA, Puncak Alam Campus, 42300 Bandar Puncak Alam, Selangor D.E., Malaysia
Zainul Zakaria, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
Halal Institute Research Institute, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
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