Phytochemical Content and <i>In Vitro</i> Antimycelial Efficacy of <i>Colocasia esculenta</i> (L), <i>Manihot esculenta</i> (Crantz) and <i>Dioscorea rotundata</i> (Poir) Leaf Extracts on <i>Aspergillus niger</i> and <i>Botryodiplodia theobromae</i>

Abstract

TheIn Vitroefficacy of aqueous leaf extracts of common edible root crops (Colocasiaesculenta,ManihotesculentaandDioscorearotundata) were investigated againstAspergillusnigerandBotryodiplodiatheobromae. The fungi were isolated from rotten tubers of yam using antibiotic-amended potatoes dextrose agar. Graded aqueous leaf extract concentrations (25 g/L, 50 g/L and 75 g/L) of each plant were applied against each test fungi on PDA plates and their mycelial growth inhibition activities were monitored for 144 hrs. Camazeb (5 – 10 g/L), a fungicide, was used as positive control agent. The phytochemical constituents of each extracts were also analyzed using standard techniques. The patterns of antifungal activities of the extracts were concentration and pathogen dependent. The most effective mean mycelial growth inhibitions were found withD.esculentaandC.esculentaagainstB.theobromae(61.9 – 80.9 %) andA.niger(63.8 – 82.8 %), respectively. Though,M.esculentaleaf extracts generally demonstrated the least antifungal activities against both pathogens, their activities were significant at 75 g/L. The antifungal potency of bothD.esculentaandC.esculentawere comparable to Camabez (chemical fungicide), which demonstrated 100 % inhibition at both 5 and 10 g/L concentrations. Higher concentrations of saponins (5.64 - 6.71 mg/100g), tannins (4.42 – 7.23 mg/100g) and flavonoids (3.64 – 5.25 mg/100g) were detected in the extracts, and could probably be linked to the observed antifungal activities. Findings from this study showed thatD.esculenta,C.esculentaandM.esculentaposses bioactive molecules that could be exploited in the bio-control of phyto-pathogens of tubers crops, which are the main staple food in most tropical countries.

In vitro efficacy of some plant aqueous extracts against two species of Lasiodiplodia associated to mango decline in Burkina Faso

“…Findings of this study revealed that the effectiveness of extracts increased as their dose increased. This is in agreement with earlier report (Ehiobu and Ogu, 2018). They reported that M. esculenta leaf extracts at concentrations (25 g/l and 50 g/l) generally demonstrated least antifungal activities against B. theobromae and A. niger, their activities being significant at 75 g/l.…”

“…Each treatment was replicated in ten plates. The rate of inhibition (PI) area induced by each treatment on the both fungal was calculated follow Ehiobu and Ogu, (2018) with formula :…”

Effect of household processing on nutritional and antinutritional composition, mineral-mineral ratios, and functional properties of Colocasia leaves

“…Colocasia , also known as Taro, is an orphan green leafy vegetable, whose leaves are a rich source of micronutrients viz., iron (10–11.7 mg 100 g −1 ), zinc (0.8–4.2 mg 100 g −1 ), potassium (0.2–1.8 g 100 g −1 ), copper (0.8 mg 100 g −1 ) and bioactive compounds including carotenoids, anthraquinones, caffeic acid, catechin, chlorogenic acid, coumaric acid, glucaric acid, vitexin, luteolin scoparin, shaftoside, and sinapic acid [ 1 , [22] , [23] , [24] ]. Similar to other green leafy vegetables the phytochemicals found in Colocasia are also responsible for critical biological activities like anti-bacterial, anti-compulsive, anti-diabetic, anti-hemorrhagic, anti-hepatotoxic, anti-hypertensive, and anti-cancerous properties [ 1 ].…”