Abstract
Introduction: Adansonia digitata L (baobab) is a forest tree, primarily in Africa and Asia. Fruit pulp extract of baobab possesses anti-inflammatory, hepatoprotective, anticlastogenic and other medicinal properties.This study evaluates the in vitro antioxidant and anticancer potentials of the aqueous extract of the fruit pulp of baobab and its fractions.
Methods: Cold extraction was done on the pulp for 72 h. The extract was filtered and concentrated; and then resuspended in water and sonicated. The mixture was sequentially fractionated to obtain n-hexane fraction (NHF), chloroform fraction (CRF), ethyl acetate fraction (EAF), n-butanol fraction (NBF) and residual aqueous fraction (AQF).The DPPH, ABTS, nitrite scavenging capacity and reducing antioxidant power assays were determined spectrophotometrically. Anticancer activity on A-549, KB, T-24 and A-498 cell lines was evaluated using sulphurhodamin B assay.
Results: The DPPH radical scavenging activity indicates that NBF has IC50 (43.44µg/mL) closest to that of the standard (Ascorbic acid) (27.22 µg/mL). For ABTS scavenging activity, NBF with IC50 value of 38.28µg/mL is closest to the standard (7.41µg/mL). For nitrite scavenging capacity, EAF has IC50 value (66.05µg/mL) closest to the standard (35.52µg/mL). Overall antioxidant results showed that NBF fraction has the highest antioxidant capacity of all the fractions. The various fractions were not significantly cytotoxic. However, morphological observation with
phase contrast microscope showed that CRF, EAF and NBF induced cytotoxic effects on human oral cancer cells (KB).
Conclusion: Aqueous extract of the fruit pulp of baobab and its fractions could be applied as natural sources of antioxidant and the fractions are cytotoxic on KB cells.
Keywords: Adansonia digitata, Antioxidant activity, Cytotoxicity, anticancer activity, aqueous extract, sulphurhodamin B assay.
Résumé
Contexte: Adansonia digitata L (baobab) est un arbre forestier, principalement en Afrique et en Asie. L’extrait de pulpe de fruit de baobab possède des propriétés anti-inflammatoires, hépatoprotectrices, anticlastogéniques et autres. Cette étude évalue les potentiels antioxydants et anticancéreux in vitro de l’extrait aqueux de pulpe de fruit de baobab et de ses fractions.
Méthodes: Une extraction à froid a été effectuée sur la pulpe pendant 72 h. L’extrait a été filtré et concentré; puis remis en suspension dans l’eau et soniqué. Le mélange a été fractionné séquentiellement pour obtenir une fraction de n-hexane (NHF), une fraction de chloroforme (CRF), une fraction d’acétate d’éthyle (EAF), une fraction de n-butanol (NBF) et une fraction aqueuse résiduelle (AQF). Le DPPH, l’ABTS, la capacité de piégeage des nitrites et les dosages de pouvoir antioxydant réducteur ont été déterminés par spectrophotométrie. L’activité anticancéreuse sur la ligne des cellules A-549, KB, T-24 et A-498 a été évaluée en utilisant un dosage de sulfurhodamine B.
Résultats:L’activité de piégeage des radicaux DPPH indique que le NBF a une CI50 (43,44 µg / mL) plus proche de celle du standard (acide ascorbique) (27,22 µg / mL). Pour l’activité de piégeage ABTS, le NBF avec une valeur IC50 de 38,28 µg / mL est le plus proche de la norme (7,41 µg / mL). Pour la capacité de piégeage des nitrites, l’EAF a la valeur IC50 (66,05 µg / mL) la plus proche de la norme (35,52 µg / mL). Les résultats globaux des antioxydants ont montré que la fraction NBF a la capacité antioxydante la plus élevée de toutes les fractions. Les différentes fractions n’étaient pas significativement cytotoxiques. Cependant, l’observation morphologique au microscope à contraste de phase a montré que le CRF, l’EAF et le NBF induisaient des effets cytotoxiques sur les cellules cancéreuses orales humaines (KB).
Conclusion: L’extrait aqueux de pulpe de fruit de baobab et ses fractions pourrait être appliqué comme source naturelle d’antioxydant et les fractions sont cytotoxiques sur les cellules KB.
Mots clés: Adansonia digitata, activité antioxydante, cytotoxicité, activité anticancéreuse, extrait aqueux, dosage de sulfurhodamine
B.
Correspondence: Prof. Oyeronke A. Odunola, Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan. Nigeria. E-mail: ronodunola@yahoo.com and aygokea@gmail.com
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