Comparative antimalarial, toxicity and mito-protective effects of Diospyros mespiliformis Hochst. ex A. DC. and Mondia whitei (Hook.f.) Skeels on Plasmodium berghei infection in mice

Traditional Uses, Pharmacological Activities, and Phytochemical Analysis of Diospyros mespiliformis Hochst. ex. A. DC (Ebenaceae): A Review

Diospyros mespiliformis Hochst. ex. A. DC is widely distributed throughout Africa and around the world. It is utilized ethnobotanically to treat fevers, wounds, malaria, diabetes mellitus, and other diseases. This review aims to provide an exhaustive overview of the traditional uses, pharmacology, and phytochemical analysis of D. mespiliformis, with the objective of identifying its therapeutic potential for further research. Scientific resources, including Google Scholar, Science Direct, Web of Science, Pub Med, and Scopus, were used to find pertinent data on D. mespiliformis. Secondary metabolites tentatively identified from this species were primarily terpenoids, naphthoquinones, phenolics, and coumarins. D. mespiliformis has been reported to demonstrate pharmacological activities, including antimicrobial, antiproliferative, antiparasitic, antioxidant, anti-inflammatory, antiviral, anti-hypersensitivity, and antidiabetic properties. The phytochemicals and extracts from D. mespiliformis have been reported to have some pharmacological effects in in vivo studies and were not toxic to the animal models that were utilized. The D. mespiliformis information reported in this review provides researchers with a comprehensive summary of the current research status of this medicinal plant and a guide for further investigation.

Ethnomedicinal plants used for malaria treatment in Rukungiri District, Western Uganda

BACKGROUND

Malaria remains a major global health challenge and a serious cause of morbidity and mortality in sub-Saharan Africa. In Uganda, limited access to medical facilities has perpetuated the reliance of indigenous communities on herbal medicine for the prevention and management of malaria. This study was undertaken to document ethnobotanical knowledge on medicinal plants prescribed for managing malaria in Rukungiri District, a meso-endemic malaria region of Western Uganda.

METHODS

An ethnobotanical survey was carried out between May 2022 and December 2022 in Bwambara Sub-County, Rukungiri District, Western Uganda using semi-structured questionnaire. A total of 125 respondents (81 females and 44 males) were randomly selected and seven (7) key informants were engaged in open interviews. In all cases, awareness of herbalists on malaria, treatment-seeking behaviour and herbal treatment practices were obtained. The ethnobotanical data were analyzed using descriptive statistics, informant consensus factor and preference ranking.

RESULTS

The study identified 48 medicinal plants belonging to 47 genera and 23 families used in the treatment of malaria and its symptoms in the study area. The most frequently cited species were Vernonia amygdalina, Aloe vera and Azadirachta indica. Leaves (74%) was the most used plant organ, mostly for preparation of decoctions (41.8%) and infusions (23.6%) which are administered orally (89.6%) or used for bathing (10.4%).

CONCLUSIONS

Indigenous knowledge of medicinal plants used as prophylaxis and for treatment of malaria still exist among the local communities of Bwambara Sub-County. However, there is a need to investigate the antimalarial efficacy, phytochemical composition and safety of species (such as Digitaria abyssinica and Berkheya barbata) with high percentage use values to validate their use.

DNA Barcoding of Endangered and Rarely Occurring Plants in Faifa Mountains (Jazan, Saudi Arabia)

Conservation of plant genetic resources, especially threatened species, is an important topic in biodiversity. It is a field that requires prior knowledge of the target species, in addition to correct identification and taxonomic description. In botany, the identification of plant species traditionally relies on key morphological descriptions and anatomical features. However, in complex species and tree plants, molecular identification can facilitate identification and increase species delimitation accuracy. In the Faifa mountains of Jazan province in Saudi Arabia, 12 rarely occurring plants were recorded and identified using two DNA barcoding regions (i.e., rbcL and ITS). All the samples were successfully amplified, sequenced, and analyzed using the standard DNA barcode protocol, and this resulted in the clear and accurate identification of 11 out of the 12 sampled species. A total of five species were in agreement in terms of both morpho- and molecular-based identification. Four and two species were identified based solely on ITS and rbcL phylogenetics, respectively. The geographic distribution records of the identified species showed that some species were distributed at a distance far from their usual region, while others were reported in proximate regions and localities. Some species were found to be medicinally important and required additional conservation plans.

A new acylated flavone glycoside, in vitro antioxidant and antimicrobial activities from Saudi Diospyros mespiliformis Hochst. ex A. DC (Ebenaceae) leaves

Phytochemical investigation of Diospyros mespiliformis leaves resulted in the isolation of new acylated flavone isoscutellarein 7-O-(4'''-O-acetyl)-β-allopyranosyl(1''' → 2'')-β-glucopyranoside (1), along with eight known flavonoid metabolites, luteolin 3',4',6,8-tetramethyl ether (2), luteolin 4'-O-β-neohesperidoside (3), luteolin 7-O-β-glucoside (4), luteolin (5), quercetin (6), quercetin 3-O-β-glucoside (7), quercetin 3-O-α-rhamnoside (8), and rutin (9). Their structures were identified by analysis of spectroscopic (UV, NMR, and MS) data, as well as by acid hydrolysis for the isolated glycosides. The antioxidant activity of D. mespiliformis metabolites was determined by the DPPH radical-scavenging assay. The new acylated flavone (1) and flavonol O-rhamnoside (8) displayed the highest antioxidant activities with IC₅₀ values 15.46 and 12.32 μg/mL, respectively, with respect to the antioxidant ascorbic acid (IC₅₀ value 10.62 μg/mL). In addition, the isolated flavonoids were evaluated against four human pathogenic bacteria where the methylated flavone (2) exhibited potent activity against Escherichia coli with inhibition zone 34 mm, and mild activity of flavonol O-rhamnoside (8) against Staphylococcus aureus with MIC value 9.77 μg/mL. According to the MBC/MIC ratio, the antibacterial activity of the isolated flavonoids was considered flavonoid 2 is bactericidal nature against S. aureus, and flavonoids 3 and 4 are bactericidal against E. coli.

Antimalarial and Erythrocyte Membrane Stability Properties of Globimetula braunii (Engle Van Tiegh) Growing on Cocoa in Plasmodium berghei-Infected Mice

Introduction

Resistant malaria is a fatal disease. Globimetula braunii (African Mistletoe) is traditionally used for malarial treatment but this fact has not been scientifically reported.

Methods

Plasmodium berghei (NK65)-infected male Swiss mice (20±2 g) were treated orally and once daily with 100, 200, and 400 mg/kg BW of methanol extract and its respective hexane, dichloromethane and ethyl acetate fractions for 9 days. P-alaxin was used as control drug P. berghei (ANKA)-infected mice were then treated with the most potent fraction for 5 days. Parasitemia and parasite clearance were determined by microscopy, while hematological parameters, heme, hemozoin, and mouse erythrocyte membrane stabilisation were assayed. The phytochemicals in the most potent fraction were identified using gas chromatography-mass spectrometry.

Results

Hexane fraction (HF)-treated mice (400 mg/kg BW) had the least mean parasite load (0.00 ± 0.00; 0.14 ± 0.05%) and highest clearance (100 ± 0.00; 75.50 ± 4.95%) compared with infected control (9.81 ± 0.09; 6.84 ± 0.09%) in susceptible and resistant models, respectively. Hexane fraction modulated hematological indices, minimised erythrocyte membrane damage in heat-induced (2.18 ± 0.94%) and hypotonic solution-induced (7.93 ± 0.93%) compared to artequin (5.05 ± 2.18; 6.38 ± 0.33%) and P-alaxin (67.45 ± 5.15; 56.78 ± 1.10%) in both models of membrane stabilisation, respectively. Hexane fraction (P<0.01) increased heme and decreased hemozoin contents. Friedelan-3-one was identified as the most abundant triterpene.

Conclusion

The results indicated that G. braunii has anti-plasmodial properties and minimally dis-stabilised erythrocyte membrane. The major findings in this study are that n-hexane fraction of G. braunii possess excellent and moderate antiplasmodial activity against susceptible and resistant P. berghei, respectively. This was reflected via decreased parasite load, improved hematological parameters, increased heme and decreased hemozoin contents. Friedelan-3-one, a major constituent of the n-hexane fraction, may be responsible for this activity.

Anti-Inflammatory Potentials of the n-Hexane Fraction of Alstonia boonei Stem Bark in Lipopolysaccharide-Induced Inflammation in Wistar Rats

Background

Inflammation is a protective response of the host to infections and tissue damage and medicinal plants have been used to regulate inflammatory response. The phytochemical contents of the n-hexane fraction of Alstonia boonei and their anti-inflammatory potentials in lipopolysaccharide-induced inflammation were investigated in rat liver.

Materials and Methods

A quantity of 5 mg/kg lipopolysaccharide (LPS) was used to induce inflammation in twenty-five male Wistar rats, grouped (n = 5) and treated as follows: negative control (10 mL/kg saline), positive control (1 mg/kg ibuprofen); 50, 100 and 20 mg/kg of the n-hexane fraction of Alstonia boonei were administered to test groups. In another experiment, twenty rats (n = 5, without LPS) were administered the same doses of the n-hexane fraction of A. boonei and ibuprofen for seven days. At the end of the experiment, animals were sacrificed, serum was obtained from blood and liver mitochondria isolated in a refrigerated centrifuge. Mitochondrial permeability transition (mPT) pore opening and mitochondrial F₀F₁ ATPase (mATPase) were determined spectrophotometrically. Serum interleukins 1β, 6 (IL-1β, IL-6), tumour necrosis factor alpha (TNF-α), C-reactive protein (CRP) and creatine kinase (CK), gamma glutamyl transferase (GGT), aspartate and alanine aminotransferases (AST and ALT,) of the animals in which inflammation was induced using LPS but treated with graded doses of n-hexane fraction of A. boonei were determined using the ELISA technique. The phytochemical contents of the n-hexane fraction of A. boonei were determined using ultra performance liquid chromatography-tandem mass spectrometer (UHPLC-MS).

Results

Calcium induced mPT in 8 fold and LPS induced mPT 14 fold in the negative control while the n-hexane fraction reversed mPT in the treated groups (50, 100 and 200 mg/kg) to 2, 4, 4 folds, respectively. LPS treatment of the negative group enhanced F₀F₁ mATPase activity, increased CRP, TNF-α, IL-1β, IL-6 levels as well as CK, AST, ALT and GGT activities. These values were significantly reduced by 100 and 200 mg/kg of the n-hexane fraction. UHPLC-MS analysis of the fraction revealed the presence of terpenoids, phenolics and sphingolipids.

Conclusion

These results showed that bioactive phytochemicals present in the n-hexane fraction of A. boonei were not toxic, have an anti-inflammatory effect and could be used for the treatment of inflammatory diseases.

Studies on the mitochondrial, immunological and inflammatory effects of solvent fractions of Diospyros mespiliformis Hochst in Plasmodium berghei-infected mice

The use of medicinal plants in the treatment of malaria is gaining global attention due to their efficacy and cost effectiveness. This study evaluated the bioactivity-guided antiplasmodial efficacy and immunomodulatory effects of solvent fractions of Diospyros mespiliformis in mice infected with a susceptible strain of Plasmodium berghei (NK 65). The crude methanol extract of the stem of D. mespiliformis (DM) was partitioned between n-hexane, dichloromethane, ethyl acetate and methanol. Male Swiss mice (20 ± 2 g) infected with P. berghei were grouped and treated with vehicle (10 mL/kg, control), Artemether lumefantrine (10 mg/kg), 100, 200 and 400 mg/kg of n-hexane, dichloromethane, ethyl acetate and methanol fractions of D. mespiliformis for seven days. Blood was obtained for heme and hemozoin contents while serum was obtained for inflammatory cytokines and immunoglobulins G and M assessments. Liver mitochondria were isolated for mitochondrial permeability transition (mPT), mitochondrial F1F0 ATPase (mATPase) and lipid peroxidation (mLPO) assays. The GC-MS was used to identify the compounds present in the most potent fraction. The dichloromethane fraction had the highest parasite clearance and improved hematological indices relative to the drug control. The heme values increased, while the hemozoin content significantly (P < 0.05) decreased compared with the drug control. The highest dose of HF and MF opened the mPT pore while the reversal effects of DF on mPT, mATPase and mLPO were dose-dependent. The levels of IgG, IgM and TNFα in the DF group were significantly higher than the drug control, while the IL-1β and IL-6 values did not vary linearly with the dose. Lupeol and Stigmastan-3,5-diene were the most abundant phytochemicals in the DF. The outcome of this study showed that the DF has immunomodulatory effects in infected mice, reduced proliferation of the malaria parasite and thus protect liver cells.

Coumarin's Anti-Quorum Sensing Activity Can Be Enhanced When Combined with Other Plant-Derived Small Molecules

Coumarins are class of natural aromatic compounds based on benzopyrones (2H-1-benzopyran-2-ones). They are identified as secondary metabolites in about 150 different plant species. The ability of coumarins to inhibit cell-to-cell communication in bacterial communities (quorum sensing; QS) has been previously described. Coumarin and its derivatives in plant extracts are often found together with other small molecules that show anti-QS properties too. The aim of this study was to find the most effective combinations of coumarins and small plant-derived molecules identified in various plants extracts that inhibit QS in Chromobacterium violaceum ATCC 31532 violacein production bioassay. The coumarin and its derivatives: 7-hydroxycoumarin, 7.8-dihydroxy-4-methylcoumarin, were included in the study. Combinations of coumarins with gamma-octalactone, 4-hexyl-1.3-benzenediol, 3.4.5-trimethoxyphenol and vanillin, previously identified in oak bark (Quercus cortex), and eucalyptus leaves (Eucalyptus viminalis) extracts, were analyzed in a bioassay. When testing two-component compositions, it was shown that 7.8-dihydroxy-4-methylcoumarin, 4-hexyl-1.3-benzendiol, and gamma-octalactone showed a supra-additive anti-QS effect. Combinations of all three molecules resulted in a three- to five-fold reduction in the concentration of each compound needed to achieve EC50 (half maximal effective concentration) against QS in C. violaceum ATCC 31532.