In this study, we identified bioactive compounds from the ethanolic extracts of the leaves, stem bark and root bark of Acalypha wilkesiana through GC-MS analysis and investigated the effects of these extracts on some of the enzymes linked to type 2 diabetes. Plant parts were extracted sequentially with ethyl acetate, ethanol and water. GC-MS analysis revealed the presence of long-chain alkyl acids, esters, ketones and alcohols including phytol and phytol acetate along with some secondary metabolites such as xanthone, vitamin E and various types of sterols including stigmasterol, campesterol and sitosterol. Ethanolic extracts of all the parts showed a dose- -dependent inhibition of α-glucosidase and α-amylase activity. The extracts also demonstrated anti-lipase activity. The ethanolic extract of root bark showed the highest inhibition of enzymes compared to other extracts. The EC50 values (concentrations for 50 % inhibition) of α-glucosidase, α-amylase and lipase inhibition were 35.75 ± 1.95, 6.25 ± 1.05 and 101.33 ± 5.21 μg mL-1, resp. The study suggests that A. wilkesiana ethanolic extracts have the ability to inhibit the activity of enzymes linked to type 2 diabetes. Further studies are needed to confirm the responsible bioactive compounds in this regard.
1. IDF Diabetes Atlas, 8th ed., International Diabetes Federation, Brussels 2017; http://www.diabetesatlas. org; last access date April 30, 2018
2. G. Roglic, WHO Global report on diabetes: A summary, Int. J. Noncom. Dis. 1 (2016) 3-8.
3. M. Lakshmi, K. Rani and T. Reddy, A review on diabetes mellitus and the herbal plants used for its treatment, Asian J. Pharm. Clin. Res. 5 (2012) 15-21.
4. A. S. Al-Goblan, M. A. Al-Alfi and M. Z. Khan, Mechanism linking diabetes mellitus and obesity, Diab. Metab. Syndr. Obes. 7 (2014) 587-591; https://doi.org/10.2147/dmso.s67400
5. D. K. Tobias, A. Pan, C. L. Jackson, E. J. O’reilly, E. L. Ding, W. C. Willett, J. E. Manson and F. B. Hu, Body-mass index and mortality among adults with incident type 2 diabetes, New Engl. J. Med. 370 (2014) 233-244; https://doi.org/10.1056/NEJMoa1304501
6. E. Levelt, M. Pavlides, R. Banerjee, M. Mahmod, C. Kelly, J. Sellwood, R. Ariga, S. Thomas, J. Francis and C. Rodgers, Ectopic and visceral fat deposition in lean and obese patients with type 2 diabetes, J. Am. Coll. Cardiol. 68 (2016) 53-63; https://doi.org/10.1016/j.jacc.2016.03.597
7. S. Kumar, S. Narwal, V. Kumar and O. Prakash, α-glucosidase inhibitors from plants: A natural approach to treat diabetes, Pharmacogn. Rev. 9 (2011) 19-29; https://doi.org/10.4103/0973-7847.79096
8. M. Yilmazer-Musa, A. M. Griffith, A. J. Michels, E. Schneider and B. Frei, Inhibition of α-amylase and α-glucosidase activity by tea and grape seed extracts and their constituent catechins, J. Agric. Food Chem. 60 (2012) 8924-8929; https://doi.org/doi:
9. M. Safavi, A. Foroumadi and M. Abdollahi, The importance of synthetic drugs for type 2 diabetes drug discovery, Expert Opin. Drug Discov. 8 (2013) 1339-1363; https://doi.org/10.1517/17460441.2013.837883
10. J. H. Wu, C. Foote, J. Blomster, T. Toyama, V. Perkovic, J. Sundström and B. Neal, Effects of sodiumglucose cotransporter-2 inhibitors on cardiovascular events, death, and major safety outcomes in adults with type 2 diabetes: a systematic review and meta-analysis, Lancet Diab. Endocrinol. 4 (2016) 411-419; https://doi.org/10.1016/S2213-8587(16)00052-8
11. Z. Bahadoran, P. Mirmiran and F. Azizi, Dietary polyphenols as potential nutraceuticals in management of diabetes: a review, J. Diabetes Metab. Disord. 12 (2013) Article ID 43 (9 pages); https://doi.org/10.1186/2251-6581-12-43
12. J. O. Olukunle, E. B. Jacobs and J. A. Oyewusi, Hypoglycemic and hypolipidemic effects of Acalypha wilkesiana leaves in alloxan induced diabetic rats, FASEB J. 30 (2016) Abstract No. 1269.3; https://doi.org/abs/10.1096/fasebj.30.1_supplement.1269.3
13. J. C. Ikewuchi, E. N. Onyeike, A. A. Uwakwe and C. C. Ikewuchi, Effect of aqueous extract of the leaves of Acalypha wilkesiana ‘Godseffiana’ Muell Arg (Euphorbiaceae) on the hematology, plasma biochemistry and ocular indices of oxidative stress in alloxan induced diabetic rats, J. Ethnopharmacol. 137 (2011) 1415-1424; https://doi.org/10.1016/j.jep.2011.08.015
14. U. Odoh, R. I. Ndubuokwu, S. I. Inya-Agha, P. O. Osadebe, P. F. Uzor and M. Ezejiofor, Antidiabetic activity and phytochemical screening of Acalypha wilkesiana (Euphorbiaceae) Mull Arg. roots in alloxan-induced diabetic rats, Sci. Res. Essays 9 (2014) 204-212; https://doi.org/10.5897/SRE2014.5824
15. A. Mohammed, M. A. Ibrahim and M. S. Islam, African medicinal plants with antidiabetic potentials: A review, Planta Med. 80 (2014) 354-377; https://doi.org/10.1055/s-0033-1360335
16. K. K. Igwe, A. J. Madubuike, I. E. Otuokere, C. Ikenga and F. J. Amaku, Studies on the medicinal plant Acalypha wilkesiana ethanol extract phytocomponents by GCMS analysis, Global J. Sci. Front. Res. D Agric. Vet. 16 (2016) 49-55.
17. A. O. Ademiluyi and G. Oboh, Soybean phenolic-rich extracts inhibit key-enzymes linked to type 2 diabetes (α-amylase and α-glucosidase) and hypertension (angiotensin I converting enzyme) in vitro, Exp. Toxicol. Pathol. 65 (2013) 305-309; https://doi.org/10.1016/j.etp.2011.09.005
18. L. J. Shai, P. Masoko, M. P. Mokgotho, S. R. Magano, A. Mogale, N. Boaduo and J. N. Eloff, Yeast alpha glucosidase inhibitory and antioxidant activities of six medicinal plants collected in Phalaborwa, South Africa, S. Afr. J. Bot. 76 (2010) 465-470; https://doi.org/10.1016/j.sajb.2010.03.002
19. Y. S. Kim, Y. M. Lee, H. Kim, J. Kim, D. S. Jang, J. H. Kim and J. S. Kim, Anti-obesity effect of Morus bombycis root extract: Anti-lipase activity and lipolytic effect, J. Ethnopharmacol. 130 (2010) 621-624; https://doi.org/10.1016/j.jep.2010.05.053
20. P. Panda, M. Rath, A. Pal, T. Sharma and D. Das, GC-MS analysis of bioactive compounds in the methanol extract of Clerodendrum viscosum leaves, Pharmacogn. Res. 7 (2015) 110-113; https://doi.org/10.4103/0974-8490.147223
21. P. Olofsson, M. Hultqvist, L. I. Hellgren and R. Holmdahl, Phytol: A Chlorophyll Component with Anti-inflammatory and Metabolic Properties, in Recent Advances in Redox Active Plant and Microbial Products (Eds. C. Jacob, G. K irsch, A. Slusarenko, P. Winyard a nd T. Burkholz), Springer, Dordrecht 2014, Chapter 13, pp. 345-359.
22. T. Takato, K. Iwata, C. Murakami, Y. Wada and F. Sakane, Chronic administration of myristic acid improves hyperglycemia in the Nagoya-Shibata-Yasuda mouse model of congenital type 2 diabetes, Diabetologia 60 (2017) 2076-2083; https://doi.org/10.1007/s00125-017-4366-4
23. J. Fotie and D. S. Bohle, Pharmacological and biological activities of xanthones, Anti-Infect. Agents Med. Chem. 5 (2006) 15-31; https://doi.org/10.2174/187152106774755563
24. G. Mahendran, M. Manoj, E. Murugesh, R. S. Kumar, P. Shanmughavel, K. R. Prasad and V. N. Bai, In vivo anti-diabetic, antioxidant and molecular docking studies of 1,2,8-trihydroxy-6-methoxy xanthone and 1,2-dihydroxy-6-methoxyxanthone-8-O-β-D-xylopyranosyl isolated from Swertia corymbosa, Phytomedicine 21 (2014) 1237-1248; https://doi.org/10.1016/j.phymed.2014.06.011
25. A. Mahammed, D. Kumar and S. I. Rizvi, Antidiabetic potential of some less commonly used plants in traditional medicinal systems of India and Africa, J. Intercult. Ethnopharmacol. 4 (2015) 78-85; https://doi.org/10.5455/jice.20141030015241
26. C. Luo, H. Zheng, S. Mao, M. Yang, C. Luo and H. Chen, Xanthones from Swertia mussotii and their α-glycosidase inhibitory activities, Planta Med. 80 (2014) 201-208; https://doi.org/0.1055/s-0033-1360173
27. N. Artanti, S. Tachibana, L. B. S. Kardono and H. Sukiman, Isolation of alpha-glucosidase inhibitors roduced by an endophytic fungus, Colletotrichum sp. TSC13 from Taxus sumatrana, Pak. J. Biol. ci. 15 (2012) 673-679; https://doi.org/10.3923/pjbs.2012.673.679
28. R. Mopuri, M. Ganjyagi, B. Meriga, N. A. Koorbanally and M. S. Islam, The effects of Ficus carica n the activity of enzyme related to metabolic syndrome, J. Food Drug Anal. 26 (2018) 201-210; ttps://doi.org/10.1016/j.jfda.2017.03.001
29. T. Chen, H. Li, C. Chen, L. Wei and Y. Li, Long scale preparation of specific xanthone from Swertia usotli and evaluation of its α-glucosidase inhibitory activity, J. Chromatogr. Sci. 55 (2017) 638- 644; https://doi.org/10.1093/chromsci/bmx020
30. N. Payghami, S. Jamili, A. Rustaiyan, S. Saeidnia, M. Nikan and A. R. Gohari, Alpha-amylase nhibitory activity and sterol composition of the marine algae, Sargassum glaucescens, Pharmacogn. es. 7 (2015) 314-321; https://doi.org/10.4103/0974-8490.167893
31. R. R. Wing, W. Lang, T. A. Wadden, M. Safford, W. C. Knowler, A. G. Bertoni, J. O. Hill, F. L. Brancati, A. Peters and L. Wagenknecht, Benefits of modest weight loss in improving cardiovascular isk factors in overweight and obese individuals with type 2 diabetes, Diabetes Care 34 (2011) 481-1486; https://doi.org/10.2337/dc10-2415
32. M. A. Ado, F. Abas, A. S. Mohammed and H. M. Ghazali, Anti- and pro-lipase activity of selected edicinal, herbal and aquatic plants, and structure elucidation of an anti-lipase compound, Molecules 8 (2013) 14651-14669; https://doi.org/10.3390/molecules181214651
33. K. Omage, M. A. Azeke and S. O. Omage, Evaluation of the efficacy of Acalypha wilkesiana leaves n managing cardiovascular disease risk factors in rabbits exposed to salt-loaded diets. Phytomedicine (2018) 1-7; https://doi.org/10.1186/s40816-018-0060-4