Antioxidant, antimicrobial, enzyme inhibition, and cytotoxicity guided investigation of Sideroxylon mascatense (A.DC.) T.D. Penn. leaves extracts

Indole-3-acetic acid (IAA) doping on the surface of CuO-NPs reduces the toxic effects of NPs on Lactuca sativa

CuO Nanoparticles (CuO NPs) retard the plant growth but at appropriate concentration boosts shoot growth and therefore may function as nano-carrier or nano-fertilizer. To overcome the toxic effects, NPs can be capped with plant growth regulators. In this work, CuO-NPs (30 nm) were synthesized as the carrier and capped with indole-3-acetic acid (IAA) to generate CuO-IAA NPs (30.4 nm) as toxicity mitigant molecules. Seedlings of dicots, Lactuca sativa L. (Lettuce) were exposed to 5, 10 mg Kg-1/ of NPs in the soil to analyze shoot length, fresh and dry weight of shoots, phytochemicals, and antioxidant response. Toxicity to shoot length was recorded at higher concentrations of CuO-NPs, however, a reduction in toxicity was observed for CuO-IAA nanocomposite. Concentration-dependent decrease in the biomass of plants was also observed at higher concentrations of CuO-NPs (10 mg/kg). The antioxidative phytochemicals (phenolics and flavonoids) and antioxidative response increased in plants when exposed to CuO-NPs. However, the presence of CuO-IAA NPs combats the toxic response and a significant decrease in non-enzymatic antioxidants and total antioxidative response and total reducing power potential was observed. The results demonstrate that CuO-NPs can be used as a carrier of hormones for the enhancement of plant biomass and IAA on the surface of NPs reduces the toxic effects on NPs.

Diversity and biological activities of medicinal plants of Santiago island (Cabo Verde)

Plants continue to constitute key elements of medical practice in West African countries. The Cabo Verde archipelago hosts a great diversity of medicinal plants and local markets are considered important sites for trading plants harvested by rural communities. This study has two main goals: (i) to assess the medicinal uses of native species in Santiago, the biggest island of the archipelago, and (ii) to evaluate the antioxidant, antimicrobial and antidiabetic/antihyperglycemic activities of two native trees (Tamarix senegalensis and Sideroxylon marginatum) used in traditional medicine and traded in local markets. Our results revealed that on Santiago Island, 24 native plants are used in traditional medicine. The main uses of these species (e.g., forage, timber, food and fibres), their medicinal applications, the plant parts used, their mode of administration and conservation status are presented here for the first time. Moreover, the pharmacological characterization of two native tree species revealed that hydroethanolic extracts were richer in phenolic compounds and more active than their aqueous counterparts. All the studied extracts revealed significant antioxidant properties (DPPH and FRAP assays) and were generally moderately active against Gram-positive bacteria. All the extracts inhibited the activities of the carbohydrate digestive enzymes α-glucosidase and α-amylase in a dose-dependent manner. For α-glucosidase, the detected inhibitory activity (IC₅₀ values from 2.0 ± 0.2 μg/mL to 9.9 ± 1.2 μg/mL) was significantly higher than that of acarbose, suggesting that extracts of both species can delay glucose absorption, thereby assisting in slowing down the progression of diabetes. Our findings highlight the crucial importance that medicinal plants have for the Cabo Verdean population, while also raising awareness on the need for sustainable use and conservation of native flora, and of tree species traded in local markets in particular.

Evaluation of the Polyphenolic Composition and Bioactivities of Three Native Cabo Verde Medicinal Plants

The use of medicinal plants in a variety of health conditions remains essential for the discovery of new treatments. The present study aimed to investigate the bioactive properties of three native plants from Cabo Verde Islands, namely Artemisia gorgonum Webb, Sideroxylon marginatum (Decne. ex Webb) Cout., and Tamarix senegalensis DC., contributing to the characterization of less-known medicinal plants and their potential benefits for human health. Known compounds, such as kaempferol, quercetin, caffeyolquinic, and apigenin derivatives, among others, were detected in the plant species under study. Overall, all species demonstrated good antioxidant capacity, especially the ethanolic extracts of A. gorgonum (EC50 = 0.149 mg/mL) in TBARS assay. Moreover, the ethanolic extracts of the studied plants showed cytotoxic properties against tumor cells, and again the A. gorgonum extract proved to be the most effective in inhibiting tumor growth, mainly in the CaCO₂ (GI50 = 17.3 μg/mL) and AGS (GI50 = 18.2 μg/mL) cell lines. Only the ethanolic extracts of T. senegalensis and S. marginatum demonstrated anti-inflammatory activity, albeit weak (EC50 = 35 and 43 μg/mL, respectively). The present study contributed to increased knowledge about the bioactive properties of these plants commonly used in traditional medicine, some of which was discussed for the first time, opening new perspectives for their use in a wider range of health conditions, especially in African countries, where access to modern health care is more limited.

Antioxidative-, Antimicrobial-, Enzyme Inhibition-, and Cytotoxicity-Based Fractionation and Isolation of Active Components from Monotheca buxifolia (Falc.) A. DC. Stem Extracts

The current study elaborates the pharmacological potential of the methanolic extract and its fractions of the stems of Monotheca buxifolia based on thin-layer chromatography and column chromatography analyses, exploiting biological and phytochemical assays. The results suggest that bioassay-guided isolation and fractionation led to the accumulation of biologically active components in the most active fractions that resulted in the isolation of different compounds. Structural elucidation of the purified compounds was accomplished using spectroscopic one-dimensional (¹H, ¹³C) and two-dimensional NMR (heteronuclear multiple quantum coherence, heteronuclear multiple bond coherence, and correlation spectroscopy) and spectrometric (electron ionization mass spectrometry and high-resolution electron ionization mass spectrometry) techniques. The n-hexane, CHCl₃, and EtAOc fractions led to the isolation of lupeol from different fractions. 1-Triacontanol was also isolated from the n-hexane fraction, while benzoic acid, methyl benzoate, ursolic acid, and 3-hydroxybenzoic acid were obtained from the EtOAc fraction. The compounds depicted good-to-moderate total antioxidative potential and total reducing power activity and significant free-radical scavenging activity. All the compounds showed significant urease and lipase inhibitory activity with poor-to-moderate amylase inhibition. Significant zone of inhibition was observed against different bacterial strains by the isolated compounds. This work therefore states that bioassay-guided isolation plays a vital role in the isolation of biologically active constituents that can be exploited for drug development.