In vitro antioxidant potential and antimicrobial activity of some Cameroonian plant extracts

Abstract

A study on Cameroonian edible and medicinal plants was undertaken to assess their potential as food preservatives and natural food colorants. The ultrasound-assisted technique was used for the extraction of bioactive compounds. A total of 16 extracts prepared from 7 plants (Aframomum melegueta S., Ageratum conyzoides L., Cympobogon citratus Stapf, Garcinia kola Heckel, Lantana camara L., Nauclea diderrichii, Vernonia amygdalina) were assayed to detect phytochemicals and assess antioxidant potential using the scavenging DPPH radical method and antimicrobial activity (10 mg/mL) against ten microorganisms by the agar well diffusion method. The ethanolic extract from L. camara leaves revealed the highest polyphenols and flavonoids contents. In contrast, the hexane/acetone extract from A. conyzoides and L. camara leaves had the highest chlorophyll a (Chl a) and chlorophyll b (Chl b) contents, whereas the highest carotenoid content was found in L. camara leaves. The ethanol extracts exhibited more significant antioxidant activity than hexane/acetone extracts. All seven plants (100%) inhibited the growth of at least one tested foodborne and spoilage bacteria and fungi. The germination of both Bacillus spp. spores were also affected. The hexane/acetone extracts were by far the best antimicrobial agent, and extract from L. camara leaves was one of the most effective, with a large antimicrobial spectrum. The antimicrobial activity of extracts was correlated to the amount of carotenoids and chlorophylls. HPLC-DAD revealed bioactive compounds as chlorogenic and caffeic acids found as major phenols in ethanolic extract of L. camara leaves, whereas lutein, carotene, and zeaxanthin were the specific carotenoids present in hexane/acetone extract of the same plant.

Use of Bitter Leaf (Vernonia amygdalina) Extract and Pasteurization Aim at Improving the Sensory Quality and Shelf-life of Mpedli, a Traditional Opaque Sorghum White Beer from Northern Cameroon

“…Leaves of VA are well-known for their high concentration in phytochemicals and natural phytopigments like green chlorophyll. This last component was responsible for the greenly opaque appearance of the processed mpedli samples [29] . The increase in colour of treated beer samples with storage time matched with the observation done by Cao et al [30] , who showed that the colour of beer increased linearly during storage at room temperature.…”

Production and Biochemical, Phytochemical, Sensory, and Microbiological Characterization of “Bili-Bili” and “Cochette,” Two Traditional Beers Produced from Sorghum (Sorghum bicolor) and Rice (Oryza sativa)

“…Furthermore, total coliforms and α-carotene were positively correlated (r � 0.998), as well as aerobic spore-forming bacteria and lycopene (r � 0.999). Both prior correlations show that the "cochette" samples with the poorest microbiological quality had the highest levels of polyphenols and carotenoids, both known as antimicrobials [79]. Tis could be explained by the fact that both groups of bioactive compounds had insufcient concentrations to provide an efective antimicrobial action.…”

Protective effects of ethanol-water leaf extract of Jatropha gossypiifolia on mouse virus-induced hepatitis (MHV) in male Swiss mice (Mus musculus)

“…Dezoumbe et al [15] reported significant contents of total polyphenols (21.23 ± 0.95 mgGAE/g), flavonoids (12.53 ±0.58 mgQE/g) and condensed tannins (7.13 ± 0.12 mgCE/g) in EJG compared with other tested extracts. Many previous studies reported antimicrobial and antiviral properties of polyphenolic molecules [20,21]. According to Okuda et al [22], tannins and similar compounds may provide protection to liver cells from the damaging effects of lipid peroxide by reducing lipid peroxide levels.…”