Okoli et al., 2016 Biosciences Research in Today’s World | July 2015 | Volume 1 | Pages 47-54 47 Biological effect of aqueous extract of Heinsia crinita on lipid peroxidation and angiotensin-1-converting enzyme in vitro Esther E. Nwanna*, Ganiyu Oboh, Bukola C. Adedayo, Taiwo M. Adewuni and Isaac Ejakpovi Functional Food and Nutraceutical Unit, Department of Biochemistry, Federal University of Technology, Akure, PMB 704, Akure 340001, Nigeria ABSTRACT Heinsia crinita; a common vegetable in the south-eastern part of Nigeria with the local name “Atama” have been used as a component of various herbal portions in ethnomedicine. The plant part has been previously used in the treatment of umbilical hernia and skin rashes. There is dearth of information on the scientific rationale behind the use of this plant. This study was designed to investigate the pharmacological potentials of aqueous extracts of Heinsia crinita for the management/prevention of hypertension. Fresh, matured green leaves of Heinsia crinita were harvested from a local farm in Cross River State, Nigeria. The total phenol, total flavonoids, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability and ability of the extract to chelate Fe 2+ as well as inhibition of Fe 2+ -induced lipid peroxidation in rat penile homogenate arginase and angiotensin-1-converting enzyme inhibitory activity were assessed. The results revealed that the extract had high total phenol and total flavonoid content. The extract also exhibited inhibitory effect on Arginase (EC50 = 3.93 mg/mL) and angiotensin-1-converting enzyme (ACE) (EC50 = 0.77 mg/mL). Furthermore, the extract exhibited strong antioxidant capacity as typified by DPPH scavenging and Fe 2+ chelating abilities coupled with the inhibition of Fe 2+ -induced lipid peroxidation in rat penile homogenate in vitro. The bioactive constituents with beneficial medicinal properties coupled with the antioxidant activities and its inhibitory effect on key enzymes linked with hypertension may be the mechanism by which the extract manage and/or prevent hypertension and other cardiovascular diseases. Citation: Nwanna EE, Oboh G, Adedayo BC, Adewuni TM and Ejakpovi I (2015). Biological effect of aqueous extract of Heinsia crinita on lipid peroxidation and angiotensin-1-converting enzyme in vitro. Biosciences Research in Today’s World 1: 47-54. doi:10.5281/zenodo.216579 Received May 28, 2015; Accepted July 2, 2015; Published July 19, 2015. Copyright: © 2015 Nwanna et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. BRTW is the official journal publication of BRSF. Competing Interests: The authors have declared that no competing interests exist. * E-mail: esthernwanna@gmail.com This research work was presented at the Biosciences Research Support Foundation (BRSF)’s 1 st International Conference on Biosciences Research (ICBR), Awka, Nigeria, 25-27 May 2015. Keywords: Heinsia crinita; ethnomedicine; arginase; hypertension. 1. INTRODUCTION Hypertension is a multifactorial genetic-related disease that precedes cardiovascular mortality and morbidity in developed and developing countries [1]. Renin produces angiotensin I from angiotensinogen, after which it is converted to a potent vasoconstrictor,angiotensin II, by angiotensin-1-converting enzyme (ACE). ACE also inactivates bradykinin,which has vasodilating action and promotes the secretion of aldosterone. As such, inhibition of ACE activity will yield major antihypertension benefits and this have been considered a useful therapeutic approach in the management and/or treatment of high blood pressure [2]. Dysfunction of the endothelial tissues plays a major role in the development of erectile dysfunction (ED) and this endothelium dysfunction is impaired by increased oxidative stress and inflammatory conditions [3]. Arginase expressed in the human corpus cavernosum tissue and which catalyse the conversion of L- arginine to ornithine plus urea have been implicated in ED [4] and arginase activity have been reported to increase with hyperglycemia and aging [5]. Increased arginase can also provide ornithine for synthesis of polyamines via ornithine decarboxylase (ODC) and proline/collagen via ornithine aminotransferase Biosciences Research in Today’s World Open Access freely available online ISSN: 2476-7905 Biosciences Research Support Foundation https://www.brsfoundation.org/brtw Research Article|