Phytotoxic, antifungal activities and acute toxicity studies of the crude extract and compounds fromDiospyros canaliculata

Abstract

In vitro biological activities including phytotoxic, antifungal activities as well as acute toxicity of the methanol extract, fractions and/or isolated compounds from the stem bark of Diospyros canaliculata were investigated. Well agar diffusion and macrodilution assays were used for investigating the antifungal activity. A phytotoxicity assay was performed against Lemna minor while an acute toxicity assay was performed in mice via oral administration. As a result, plumbagin (5-hydroxy-2-methyl-1,4-naphtoquinone) and two known pentacyclic triterpenes (lupeol and lupenone) were isolated from the extract. With regards the antifungal activities, the inhibition zones varied from 16.51 to 24.86 mm and from 20.50 to 25.10 mm for the extract and plumbagin, respectively. The minimum inhibitory concentrations of the extract and plumbagin ranged between 12.5-25 and 0.78-1.56 µg mL(-1), respectively. At 50 µg mL(-1), the hexane fraction showed phytotoxic activities similar to paraquat, the standard phytotoxic inhibitor. The extract was found to be non-toxic to mice after administration per os. Based on the current findings, we can conclude that this extract is non toxic, with significant phytotoxic and antifungal properties due to the presence of plumbagin.

Inhibitory activity of plumbagin produced by Drosera intermedia on food spoilage fungi

“…In fact, the obtained MIC for the purified plumbagin sample was lower than the reference antimycotic, miconazole (1.25 µg mL −1 ), while in other species, such as A. niger MUM 03.43 and A. flavus MUM 92.01, the activity was similar (Table 1). The presented results are consistent with previous works where the antifungal activity of plumbagin was reported 12, 13. Interestingly, in the previously cited studies, MIC values of the same order of magnitude (0.78 µg mL −1 ) were also obtained for A. fumigatus, A. niger and A. flavus strains against a standard solution of plumbagin, confirming the high purity of the tested sample.…”

Surface chemistry and spectroscopy studies on 1,4-naphthoquinone in cell membrane models using Langmuir monolayers

“…Among these drugs, naphthoquinones are organic molecules that form the main chemical structures of several natural compounds such as vitamin K. Some naphthoquinone derivatives reportedly have pharmacological properties presenting cytotoxicity. Many are considered antimicrobial [1,2] (antibacterial, antiviral, antifungal) and insecticidal [3], and others present antipyretic and anti-inflammatory properties [4]. The action of naphthoquinones as anti-cancer agents has been reported [5,6], with potential activity as cell membrane (tumorigenic or healthy) disruptors.…”

Plumbagin inhibits cytokinesis in Bacillus subtilis by inhibiting FtsZ assembly – a mechanistic study of its antibacterial activity

“…Plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) is a secondary plant metabolite exhibiting several biological activities, including its ability to inhibit proliferation of mammalian, fungal and bacterial cells [16][17][18][19][20]. Plumbagin has been shown to have toxicity against several pathogenic and non-pathogenic microbes [21][22][23].…”