Antimicrobial Potential of Plant Extracts and Chemical Fractions of Sideroxylon obtusifolium (Roem. & Schult.) T.D. Penn on Oral Microorganisms

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.

Green synthesized silver nanoparticles (AgNPs) from Parrotiopsis jacquemontiana (Decne) Rehder leaf extract and its biological activities

Parrotiopsis jacquemontiana (Decne) Rehder aqueous extract of leaf was used for biosynthesis of AgNPs and characterized through UV-Visible spectroscopy, X-ray diffraction, Fourier-transform-infrared, diffraction light scattering, and scanning electron microscope analysis. Moderate to strong antioxidant activity during in vitro antioxidant assays for scavenging of 2,2-diphenyl-1-picryl hydrazyl (DPPH), hydroxyl (OH), nitric oxide (NO) radicals, iron chelation, and inhibition of β-carotene bleaching was recorded with minimum IC₅₀ value (27.70 ± 2.67 μg/ml) calculated for OH radicals. The AgNPs were evaluated against six multidrug resistant human bacterial strains and minimum inhibitory concentration (MIC) along with minimum bactericidal concentration (MBC) values was determined and all were found remarkably susceptible. The bacterial strain Staphylococcus aureus was the most susceptible with MIC = 5 μg/ml and MBC = 10 μg/ml. Among six fungal strains, Fumigatus esculentum was the most susceptible with MIC and MBC of 10 μg/ml. 3-(4,5-Dimethylthiazol-2 yl)-2,5-diphenyltetrazolium bromide (MTT) screening assay against cancer cell lines (HCCLM3, HEPG2, MDA-MB 231, and MCF-7) revealed the least IC₅₀ values against HCCLM3 (74.20 ± 5.04) and MCF-7 (91.90 ± 1.17). While no cytotoxicity against normal cell lines; LO2 and MCF-10a was recorded. Parrotiopsis jacquemontiana silver nanoparticles (PJAgNPs) significantly (p > .001) prevented the migration of HCCLM3 cells in a dose-dependent style, relative to control. The wound healing potential of AgNPs in rat was found higher (p < .05) for wound contraction rates, hydroxyproline content, hemostatic and re-epithelization and regeneration efficiency in comparison to the reference group.

A proline derivative-enriched methanol fraction from Sideroxylon obtusifolium leaves (MFSOL) stimulates human keratinocyte cells and exerts a healing effect in a burn wound model

It was previously demonstrated that the methanol fraction of Sideroxylon obtusifolium (MFSOL) promoted anti-inflammatory and healing activity in excisional wounds. Thus, the present work investigated the healing effects of MFSOL on human keratinocyte cells (HaCaT) and experimental burn model injuries. HaCaT cells were used to study MFSOL's effect on cell migration and proliferation rates. Female Swiss mice were subjected to a second-degree superficial burn protocol and divided into four treatment groups: Vehicle, 1.0% silver sulfadiazine, and 0.5 or 1.0% MFSOL Cream (CrMFSOL). Samples were collected to quantify the inflammatory mediators, and histological analyses were performed after 3, 7, and 14 days. The results showed that MFSOL (50 μg/mL) stimulated HaCaT cells by increasing proliferation and migration rates. Moreover, 0.5% CrMFSOL attenuated myeloperoxidase (MPO) activity and also stimulated the release of interleukin (IL)-1β and IL-10 after 3 days of treatment. CrMFSOL (0.5%) also enhanced wound contraction, promoted improvement of tissue remodeling, and increased collagen production after 7 days and VEGF release after 14 days. Therefore, MFSOL stimulated human keratinocyte (HaCaT) cells and improved wound healing via modulation of inflammatory mediators of burn injuries.

Phytochemical investigation and antimicrobial appraisal of Parrotiopsis jacquemontiana (Decne) Rehder

BACKGROUND

Parrotiopsis jacquemontiana (Decne) Rehder. is locally used for skin infections and in wound healing. In this study we have evaluated methanol extract of its leaves and derived fractions against the clinical multi-drug resistant bacterial strains.

METHODS

P. jacquemontiana leaves powder extracted with 95% methanol (PJM) and fractionated in escalating polarity of solvents; n-hexane (PJH), chloroform (PJC), ethyl acetate (PJE), n-butanol (PJB) and the remaining as aqueous fraction (PJA). Clinical as well as environmental 19 bacterial strains and 8 fungal strains were screened for minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC). Preliminary phytochemical investigation for various phytochemical classes was also carried out.

RESULTS

PJM contained the coumarins, phenols, flavonoids, tannins, alkaloids, glycosides, saponins, sterols, phlobatannins, steroids, phytosterols, triterpenoids, acids, quinones, proteins, vitamin C, betacyanins, oils and resins while anthraquinones, phytosteroids, carbohydrates and anthocyanins were not detected. Disc diffusion assay (1 mg/disc) indicated the sensitivity of all the MDR strains of bacteria with PJM, PJE and PJB, while no inhibition was recorded with PJA. PJH and PJC inhibited the growth of all the strains of Staphylococcus aureus, Pseudomonas aeruginosa and Coagulase negative staphylococci used in this study. Maximum zone of inhibition (35.5 ± 1.32 mm) was obtained with PJM against Staphylococcus lugdenesis MDR (6197). Comparatively lower MIC (8-64 μg/ml) and MBC (32-256 μg/ml) values were recorded for PJM and PJE. In case of fungal strains only PJM, PJE and PJB markedly inhibited the growth and lower MIC (8-128 μg/ml) and MFC (32-512 μg/ml) values were determined for PJM and PJE.

CONCLUSION

The remarkable inhibition of various bacterial and fungal strains at low doses of the extract/fractions suggested the strong antibacterial, antifungal and anti-candidal potential of P. jacquemontiana leaves.