Investigation Of Antimicrobial And Antioxidant Activity Of The Methanolic Extract Of The Leaves Of Voacanga Africana Stapf. (Apocynaceae) And Psydrax Subcordata (Dc.) Bridson (Rubiaceae)

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Bamisaye Olaofe Oyawaluja
Josephine Aribiba Williams
Herbert A. B. Coker



The importance of medicinal plants in traditional and modern health care practices and in providing clues to new areas of research is now well recognised. Bacterial resistance has been increasingly reported worldwide and is one of the major causes of failure in the treatment of infectious diseases. Plant derived antioxidant could be useful as food additives to prevent food deterioration and also to impart human health and prevent oxidative stress associated diseases. Naturalbased products, including plant secondary metabolites (phytochemicals), can be exploited to ameliorate the problem of microbial resistance and oxidative stress. The choice of plants (Voacanga africana and Psydrax subcordata) for this study was based on folkloric use and literature search to authenticate the traditi on claims.


The leaves methanolic extract of Voacanga africana and Psydrax subcordata were investigated for antimicrobial and antioxidant activity. The antimicrobial activities were also evaluated using the agar well diffusion method while the antioxidant activities of the plants were evaluated using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, nitric oxide scavenging assay, lipid peroxidati on scavenging assay, total antioxidant capacity assay, total phenolic content, total flavonoid content and ferric reducing power assay.


The extracts of Voacanga africana and Psydrax subcordata significantly inhibited DPPH radical with an IC50 value of 69.2±11.6µg/ml and 106.9±5.3µg/ml respectively), inhibited lipid peroxidation (IC50 value of 65.7±13.5µg/ml and 75.4±11.6 µg/ml respectively) and also inhibited the accumulation of nitrite in vitro (IC50 value of 75.1±11.7µg/ml and 80.1±12.9µg/ml respectively). The plant extracts yielded 47.8±0.07 and 65.2±0.04mg Gallic acid equivalent/100g phenolic content respecti vely, 2.8±0.05mg and 28.2±0.05mg quercetin equivalents/100g flavonoid content respectively, total antioxidant capacity of 160.6±0.05 and 110.7±0.05mg ascorbic equivalent/100g and reducing power of 0.2±0.07 and 0.2±0.05µg/ml, respecti vely. The anti microbial assay showed that Voacanga africana has activity against gram positive and gram negati ve bacteria organisms, which include Staphylococcus aureus (34.0±1.2), Bacillus subtilis (37.5±0.0) and Pseudomonas aeruginosa (35.5±0.9) at 50µg/ml. Psydrax subcordata was only active against Staphylococcus aureus (20.8±0.5). However, no antifungal activity was observed for both plants.


Voacanga africana and Psydrax subcordata possess anti oxidant and anti microbial acti viti es and these results therefore provide evidence to support their traditional uses. The observed antioxidant potentials and phenolic content of the extract suggest that the methanolic leaves extract of Voacanga africana and Psydrax subcordata is a potential source of natural antioxidants.

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Olaofe Oyawaluja, B. ., Aribiba Williams, J. ., & A. B. Coker, H. . (2019). Investigation Of Antimicrobial And Antioxidant Activity Of The Methanolic Extract Of The Leaves Of Voacanga Africana Stapf. (Apocynaceae) And Psydrax Subcordata (Dc.) Bridson (Rubiaceae). The Nigerian Journal of Pharmacy, 53(1). Retrieved from
Author Biographies

Bamisaye Olaofe Oyawaluja, Department of Pharmaceutical Chemistry,

Faculty of Pharmacy, University of Lagos

Josephine Aribiba Williams, Department of Pharmaceutical Chemistry,

Faculty of Pharmacy, University of Lagos

Herbert A. B. Coker, Department of Pharmaceutical Chemistry,

Faculty of Pharmacy, University of Lagos


Urquiag I and Leighton F (2000). Plant Polyphenol Antioxidants and Oxidative Stress. Biological Research; 33: 55 – 64.

King SR and Moran K (1996). Biological diversity, indigenous knowledge, drug discovery and intellectual property rights: creating reciprocity and maintaining relationships. Journal of Ethnopharmacology; 51 (1-3): 45-57.

Okigbo RN, Eme UE and Ogbogu S (2008). Biodiversity and Conservation of Medicinal and Aromatic Plants in Africa. Biotechnology and Molecular Biology Reviews; 3(6): 127-134.

Jamshidi-Kia F, Lorigooini Z and Amini-Khoei H.(2018). Medicinal Plants: Past History and Future Perspectives. Journal of Herbmed Pharmacology; 7 (1): 1-7.

Okigbo RN and Nmeka, IA (2005). Control of yam tuber rot with leaf extracts of Xylopia aethiopica and Zingiber officinale. African. Journal of Biotechnology; 4(8): 804-807.

Osemeobo GJ. and Ujor G (1999). Non Wood Forest Products in Nigeria. Data collection and analysis for sustainable forest management in ACP countriesLinking national and international efforts. EC-FAO partnership programme. Federal Department of Forestry, Abuja, Nigeria: p 42.

Berdy J (2012). Thoughts and facts about antibiotics: Where we are now and where we are heading. Journal of Antibiotic. 65: 385–395.

French GL (2010). The Continuing Crisis in Antibiotic Resistance. International Antimicrobial. Agents. 36: 53–S7.

Pitout JD and Laupland KB (2008). Extended-spectrum ß-lactamase-producing Enterobacteriaceae: An Emerging Publichealth Concern. Lancet Infection Disease; 8: 159–166.

Berger J, Diab-Elschahawi M and Blacky AA (2010). Matched Prospective Cohort Study on Staphylococcus Aureus and Escherichia Coli Bloodstream Infections: Extended Perspectives Beyond Resistance. American Journal of Infection Contaminant; 38: 839–845.

David MZ and Daum RS (2010). Community-associated methicillin-resistant Staphylococcus aureus: Epidemiology and clinical consequences of an emerging epidemic. Clinical Microbiology Review; 23: 616–687.

Mathers C, Fat DM and Boerma JT (2008). The Global Burden of Disease: 2014 Update. World Health Organization, Geneva, Switzerland, Scientific Research Publishing: 1-2

Halliwell B and Guferidge JC (1995). The Definition and Measurement of Antioxidants in Biological Systems. Free Radical Biological Medicine; 18: 125–126.

McCaughan JS (1999). Photodynamic therapy—a review. Drugs Aging; 15: 49–68.

Cross CE, Vander Vielt A and O'Neill C (1994). Oxidants, Antioxidants, and Respiratory Tract Lining Fluids. Environ Health Perspective; 102:185–191.

Kelly FJ, Mudway I and Krishna MT (1995). The Free Radical Basis of Air Pollution Focus on Ozone. Respiratory Medicine; 89: 647–656.

Kelly FJ and Tetley TD (1997). Nitrogen dioxide Depletes Uric Acid and Ascorbic acid but not Glutathione from Lung Lining Fluid. Biochemical Journal; 325: 95–99.

Pourcelot S, Faure H and Firoozi F (1999). Urinary 8-oxo-7, 8-dihydro-2`-deoxyguanosine and 5- (hydroxymethyl) uracil in smokers. Free Radical Research; 30:173–180.

Graeme B. (2010). Garden of Eden: The Shamanic Use of Psychoactive Flora and Fauna and the Study of Consciousness (Book Review). Australian Journal of Medical Herbalism; 22(3): 107.

Burkill HM (1985). The Useful Plants of West Tropical Africa, vols. 1-3. 2nd edn. Royal Botanic Gardens.

Agyare C, Asase A, Lechtenberg M, Niehues M, Deters A and Hensel A (2009). An Ethnopharmacological Survey and In-vitro Confirmation of Ethnopharmacological Use of Medicinal Plants Used for Wound Healing in Bosomtwi-AtwimaKwanwoma area, Ghana. Journal of ethnopharmacology; 125(3): 393-403.

Trease GE and Evans WC (1989). Pharmacognosy, 13th edition. ELBS/Bailliere Tindall, London: 345-346, 535-536, 772-773.

Murray PR, Baron EJ, Pfaller MA, Tenoer FC and Yolken HR (1995). Manual of Clinical Microbiology. 6th ed. Washington DC: ASM Press. pp. 15-18

Lino A and Deogracios O (2006). The In-vitro Antibacterial Activity of Annona senegalensis, Securidacca longipendiculata and Steanotaenia araliacea - Ugandan Medicinal plants. African Health Science; 6(1): 31-35.

Wendakoon C, Calderon P and Gagnon D (2012). Evaluation of Selected Medicinal Plants Extracted in Different Ethanol Concentrations for Antibacterial Activity against Human Pathogens. Journal of Medicinal and Aromatic Plants; 1: 60-68.

Buege J and Aust DS (1978). Microsomal lipid peroxidation. In: Fleisscher S, Packer L, eds. Methods in enzymology. New York: Academic Press. 52: 302-311.

Alisi CS and Onyeze GOC (2008). Nitric Oxide Scavenging Sbility of Ethyl Acetate Fraction of Methanolic Leaf Extracts of Chromolaena odorata (Linn.). African Journal of Biochemistry Research; 2: 145-150.

Cuendet M, Hostetmann K and Poterat O (1997). Iridoid Glucosides with Free Radical Scavenging Properties from Fagraea blumei. Helvetica Chirurgica Acta 80: 73-83.

Burits M and Bucar F (2000). Antioxidant Activity of Nigella sativa essential oil. Phytotherapy Research; 14: 323-328.

McDonald S, Prenzler PD, Antolovich M and Robards K (2001). Phenolic Content and Antioxidant Activity of Olive Extracts. Food Chemistry; 73: 73-84.

Chang C, Yang M and Wen H (2002). Estimation of Total Flavonoid Content in Propolis by Two Complementary Colorimetric Methods. Journal of Food and Drug Analysis; 10:178-182.

Ebena RUB, Madunagu BE, Ekpe ED and Otung IN (1991). Microbiological Exploitation of Cardiac Glycosides and Alkaloids from Garcinia kola, Boreria ocymoides, Kola nitida and Citrus aurantifolia. Journal of Applied Bacteriology; 71: 398-401.

Banso A and Adeyemo SO (2007). Phytochemical and Antimicrobial Evaluation of Ethanolic Extracts Draclena Mannii Bark. Nigeria Journal of Biotechnology; 18: 27-32.

Jurd L and Geissmao TA (1956). Absorption Spectra of Metal Complexes of Flavonoid Compounds. Journal of Organic Chemistry; 21: 1395-1401.