Phenolic compounds profile of water and ethanol extracts of Euphorbia hirta L. leaves showing antioxidant and antifungal properties

The bioactive chemical constituents of water and ethanol extracts of Euphorbia hirta L. leaves have been identified and quantified using an un-targeted mass spectrometric approach. The study allowed the tentative identification of 123 individual phenolic compounds and 18 non-phenolic phytochemicals, most of them described in Euphorbia hirta L. leaves for the first time. Gallotannins, hydroxybenzoic and hydroxycinnamic acids were the most abundant phenolic classes in Euphorbia hirta L. leaves, representing together the 71.5% (26.3%, 25.2% and 20%, respectively) of the total amount of identified phenolics. The main phenolic compounds detected were tri-O-galloyl-glucose isomers, feruloyl-coniferin, tetra-O-galloyl-glucose isomers, di-O-galloyl-glucose isomers, ethyl-gallic acid, protocatechuic acid-O-pentoside-O-hexoside, 5-O-caffeoyl-quinic acid trans isomer and digalloyl-quinic acid. Feruloyl-coniferin was found to be approximately six times more concentrated in the ethanol extract with respect to the water extract. The ethanol extract exhibited higher ABTS (1338.3 ± 85.3 and 802.3 ± 91.0 μmol ascorbic acid equivalent/gram of dry extract, respectively) and superoxide anion (2014.6 ± 78.6 and 1528.0 ± 111.7 μmol ascorbic acid equivalent/gram of dry extract, respectively) scavenging abilities than the water extract. Additionally, the ethanol extract also showed a remarkable anti-fungal effect against Fusarium oxysporum f. sp. vasinfectum, Alternaria solani and Rhizoctonia solani. This study provides new information about Euphorbia hirta L., offering reasons to promote this plant species as rich source of phenolics and an excellent source of antifungal molecules that might have a prospective use in controlling fungal diseases of vegetable crops

Activity of extracts from three tropical plants towards fungi pathogenic to tomato (Solanum lycopersicum)

Antifungal properties were assessed of water and ethanol extracts from the pan-tropical plants Oxalis barrelieri L., Stachytarpheta cayennensis L., and Euphorbia hirta L. against Fusarium oxysporum f. sp. vasinfectum, Alternaria solani Sorauer, and Rhizoctonia solani Kuhn. The plant extracts inhibited fungal growth in vitro at 1.25-20 mg mL-1, and the degrees of inhibition increased in a dose-dependent manner. Ethanol extracts from the plants inhibited fungal growth by 80-100%, while water extracts showed less antifungal activity, with maximum growth inhibition of 62%. Growth inhibition from ethanol extracts was two- to three-fold greater than for water extracts at equivalent concentrations. Antifungal activity of the extracts varied with their content and composition of phenolics, flavonoids, tannins, and alkaloids. In greenhouse experiments, spraying tomato plants (Solanum lycopersicum L.) with ethanol extract from E. hirta at 2.5 mg mL-1 did not cause phytotoxicity, and increased plant size, when compared to untreated plants. Spraying E. hirta ethanol extract on tomato plants infected by R. solani reduced disease severity up to 80%, when compared to non-sprayed plants. These results demonstrate potential of leaf extracts from E. hirta, O. barrelieri, and S. cayennensis as biofungicides for the control of R. solani, A. solani, and F. oxysporum, which are among the most important causal agents of tomato diseases

Antifungal potential of extracts from three plants against two major pathogens of celery (apium graveolens l.) in Cameroon

With the aim of contributing to natural control of plant pathogens, the antifungal activity of 11 extracts from 3 Cameroonian plants namely, Drypetes gossweileri, Eucalyptus tereticornis and Sida acuta was evaluated against Acremonium apii and Colletotrichum dematium, respectively causal agents of brown spot and anthracnose diseases of celery (Apium graveolens L.). The supplemented media technique was used to assess the inhibition of both fungi mycelial growth by essential oils, ethanol,hot water and cold water extracts. The essential oils exhibited the highest antifungal activity at 50 ppm with essential oil from D. gossweileri; and 6000 ppm and 7000 ppm, against C. dematium and A. apii, respectively, with essential oil from E. tereticornis. Ethanol and aqueous extracts displayed a moderate inhibitory activity with the best activity obtained from D. gossweileri ethanol extracts (90.31% and 67.53%, respectively, against A. apii and C. dematium at 10000 ppm). The fungitoxic potential of essential oils was comparative to the synthetic fungicide used as positive control. Phytochemical screening of solvent extracts revealed a diverse composition in secondary metabolites and stronger inhibitory effects were recorded with extracts rich in alkaloids, phenols, anthraquinones and saponines. These findings suggest a promising potential of essential oils and ethanol extracts for botanicals control of celery fungal pathogens

Armillaria root rot threatens Cameroon's Penja pepper (Piper nigrum L.)

Penja pepper (Piper nigrum) produced in Cameroon has long been recognized for its exceptional organoleptic quality. The pepper vine is grown using a support tree (Spondias mombin) in Cameroon. A root disease is associated with plant deaths in both plants. The disease symptoms are characterized by collar cracking and gummosis and the disease was tentatively identified as Armillaria root rot. In this work the extent of the problem was characterized by surveying 35 farms in Cameroon. Samples were taken from diseased support trees and pepper vines. Support trees exhibiting typical symptoms were found in approximately one third of the surveyed farms. In these farms, disease incidence and Pepper vine mortality ranged from 1.3 to 50% and 1.2 to 87.7%, respectively. Analysis of the ribosomal internal transcribed spacer region (ITS) locus suggested that the isolates collected from S. mombin and P. nigrum are most likely, which is a first for both hosts, represented by Armillaria camerunensis (Henn.) Volk & Burdsall, a fungus previously associated with declining cacao trees in Cameroon. Given the increasing demand for Penja pepper and the great damaging potential of this root rot, research on management strategies should be prioritized

Armillaria root rot threatens Cameroon’s Penja pepper (Piper nigrum L.)

Penja pepper (Piper nigrum) produced in Cameroon has long been recognized for its exceptional organoleptic quality. The pepper vine is grown using a support tree (Spondias mombin) in Cameroon. A root disease is associated with plant deaths in both plants. The disease symptoms are characterized by collar cracking and gummosis and the disease was tentatively identified as Armillaria root rot. In this work the extent of the problem was characterized by surveying 35 farms in Cameroon. Samples were taken from diseased support trees and pepper vines. Support trees exhibiting typical symptoms were found in approximately one third of the surveyed farms. In these farms, disease incidence and Pepper vine mortality ranged from 1.3 to 50% and 1.2 to 87.7%, respectively. Analysis of the ribosomal internal transcribed spacer region (ITS) locus suggested that the isolates collected from S. mombin and P. nigrum are most likely, which is a first for both hosts, represented by Armillaria camerunensis (Henn.) Volk & Burdsall, a fungus previously associated with declining cacao trees in Cameroon. Given the increasing demand for Penja pepper and the great damaging potential of this root rot, research on management strategies should be prioritized.CIRAD, IRAD, the University of Pretoria and through the “Debt reduction-development contract (C2D) France Cameroon” Poivre de Penja project.https://link.springer.com/journal/40858am2021BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant PathologyPlant Production and Soil Scienc