Antibacterial activity of two biflavonoids from Garcinia livingstonei leaves against Mycobacterium smegmatis

Unraveling Amentoflavone's Therapeutic Potential in Alzheimer's Disease: A Preclinical Assessment

Alzheimer's disease is one of the neurodegenerative diseases which causes cognition deficit. There are currently few medications available to treat Alzheimer's disease, even though researchers have devoted a great deal of time studying the condition and offering many benefits. Thus, only a few drugs are available for the treatment of Alzheimer's disease. Amentoflavone is a dietary component found in many plants and herbs that has several health advantages. Amentoflavone has demonstrated strong protective benefits against a range of brain illnesses in preclinical trials, most frequently in Alzheimer's disease. Amentoflavone, a biflavonoid, can be identified in a variety of herbs upon isolation. Considering the beneficial properties of this compound, this review emphasizes the pharmacological effects and botanical sources of amentoflavone, as well as the compound's benefits and possible applications in the treatment of Alzheimer's disorders.

Multi-target action of Garcinia livingstonei extract and secondary metabolites against fatty acid synthase, α-glucosidase, and xanthine oxidase

Garcinia livingstonei is a traditional herbal medicine that showed beneficial health effects and bioactivities. Four compounds have been isolated from the plant leaves and were elucidated as lupeol, betulin, podocarpusflavone A, and amentoflavone. The inhibitory activities of G. livingstonei extract and isolated metabolites against fatty acid synthase (FAS), α-glucosidase, and xanthine oxidase (XO) were investigated in vitro. The affinity of the compounds toward the studied enzymes was investigated in silico. The plant extract inhibited FAS, α-glucosidase, and XO with IC50 values of 26.34, 67.88, and 33.05 µg/mL, respectively. Among the isolated metabolites, betulin exhibited the most inhibitory activity against α-glucosidase and XO with IC50 values of 38.96 and 30.94 µg/mL, respectively. Podocarpusflavone A and betulin were the most potent inhibitors of FAS with IC50 values of 24.08 and 27.96 µg/mL, respectively. Computational studies corroborated these results highlighting the interactions between metabolites and the enzymes. In conclusion, G. livingstonei and its constituents possess the potential to modulate enzymes involved in metabolism and oxidative stress.

Standardization and quantitative analysis of Araucaria Heterophylla extract via an UPLC-MS/MS method and its formulation as an antibacterial phytonanoemulsion gel

Skin infections are among the bacterial infections that present significant therapeutic challenges due to antibiotic resistance. Recently, herbal products clutched a significant attention as safe replacements for other medications but their low aqueous solubility and poor bioavailability are considered major challenges which could be circumvented via formulation. As a species of genera Araucaria, Araucaria Heterophylla possesses pharmacological activities such as antioxidant and antibacterial actions, and this study aimed to standardize the extract of the plant against 4ʹʹʹmethoxyamentoflavone (as a main component of the extract) through a validated UPLC-MS/MS method and evaluate its antibacterial activity, which was followed by loading the standardized extract into a nanoemulsion to form a phytonanoemulsion (PNE), where the design analysis and optimization were performed through a simplex lattice design. The optimized PNE (PNE 3) was then loaded into HPMC/Pluronic F-127 gel (in ratio 1:4) to sustain the release of the active constituent. The heightened penetrability of PNE 3 gel was visualized via confocal laser scanning microscopy, and its prolonged effect was proved thru an in vivo study conducted on male Wistar rats. A histopathological study revealed the safety of the formulation when applied topically. Thus, PNE gel could be a potentially broad-spectrum antibacterial drug delivery system.

Traditional Medicinal Plants as a Source of Antituberculosis Drugs: A System Review

Medicinal plants are the chief components in the different oriental formulations in different traditional medical systems worldwide. As a thriving source of medicine, the medicinal plants with antituberculosis (TB) properties inspire the pharmacists to develop new drugs based on their active components or semimetabolites. In the present review, the anti-TB medicinal plants were screened from the scientific literatures, based on the botanical classification and the anti-TB activity. The obtained anti-TB medicinal plants were categorized into three different categories, viz., 159 plants critically examined with a total 335 isolated compounds, 131 plants with their crude extracts showing anti-TB activity, and 27 plants in literature with the prescribed formula by the traditional healers. Our systemic analysis on the medicinal plants can assist the discovery of novel and more efficacious anti-TB drugs.

South Africa's Best BARK Medicines Prescribed at the Johannesburg Muthi Markets for Skin, Gut, and Lung Infections: MIC's and Brine Shrimp Lethality

Indigenous trade of medicinal plants in South Africa is a multi-million-rand industry and is still highly relevant in terms of primary health care. The purpose of this study was to identify today's most traded medicinal barks, traditionally and contemporaneously used for dermatological, gastrointestinal, and respiratory tract infections; then, to investigate the antimicrobial activity and toxicity of the respective extracts and interpret outcomes in light of pharmacokinetics. Thirty-one popularly traded medicinal barks were purchased from the Faraday and Kwa Mai-Mai markets in Johannesburg, South Africa. Information on the medicinal uses of bark-based medicines in modern commerce was recorded from randomly selected traders. The minimum inhibitory concentration (MIC) method was used for antimicrobial screening, and brine shrimp lethality was used to determine toxicity. New medicinal uses were recorded for 14 bark species. Plants demonstrating some broad-spectrum activities against tested bacteria include Elaeodendron transvaalense, Erythrina lysistemon, Garcinia livingstonei, Pterocelastrus rostratus, Rapanea melanophloeos, Schotia brachypetala, Sclerocarya birrea, and Ziziphus mucronata. The lowest MIC value of 0.004 mg/mL was observed against Staphylococcus epidermidis for a dichloromethane bark extract of E. lysistemon. The tested medicinal barks were shown to be non-toxic against the Artemia nauplii (brine shrimp) bioassay, except for a methanol extract from Trichilia emetica (69.52% mortality). Bacterial inhibition of bark extracts with minimal associated toxicity is consistent with the safety and valuable use of medicinal barks for local muthi market customers. Antimicrobial outcomes against skin and gastrointestinal pathogens are feasible because mere contact-inhibition is required in vivo; however, MIC values against respiratory pathogens require further explaining from a pharmacokinetics or pharmacodynamics perspective, particularly for ingested rather than smoked therapies.

Proximate Analyses and Amino Acid Composition of Selected Wild Indigenous Fruits of Southern Africa

A literature survey revealed that several wild indigenous Southern African fruits had previously not been evaluated for their proximate and amino acid composition, as well as the total energy value (caloric value). Fourteen species including Carissa macrocarpa, Carpobrotus edulis, Dovyalis caffra, Halleria lucida, Manilkara mochisia, Pappea capensis, Phoenix reclinata, and Syzygium guineense were analyzed in this study. The nutritional values for several species such as C. edulis, H. lucida, P. reclinata, and M. mochisia are being reported here for the first time. The following fruits had the highest proximate values: C. macrocarpa (ash at 20.42 mg/100 g), S. guineense (fat at 7.75 mg/100 g), P. reclinata (fiber at 29.89 mg/100 g), and H. lucida (protein at 6.98 mg/100 g and carbohydrates at 36.98 mg/100 g). Essential amino acids such as histidine, isoleucine, lysine, methionine, phenylalanine, tryptophan, and valine were reported in all studied indigenous fruits. The high protein content in H. lucida was exhibited by the highest amino acid quantities for histidine. However, the fruits are a poor source of proteins since the content is lower than the recommended daily intake. The jacket-plum (Pappea capensis), on the other hand, meets and exceeds the required daily intake of lysine (0.0003 g/100 g or 13 mg/kg) recommended by the World Health Organization.

Exploring how structural changes to new Licarin A derivatives effects their bioactive properties against rapid growing mycobacteria and biofilm formation

Several species of rapidly growing mycobacteria (RGM) have been associated with biofilms in areas such as biomedical devices, water distribution systems, cosmetic surgery, and catheter-related blood infections. Biofilms which exhibit antimicrobial resistance such as those formed by the genus Mycobacterium pose a significant risk to health and are of particular interest to researchers. Licarin A (a neolignan found in numerous plant species e.g. nutmeg) has been reported to show a wide range of biological actions including anti-inflammatory, antioxidant, and antibacterial properties. The aim of this study was to prepare a set of Licarin A derivatives and investigate the impact of specific structural changes on its antimycobacterial ability, and its effect on the biofilm formation of RGM species. Initially, the phenolic sub-unit and alkenyl side chain of Licarin A were modified to create derivatives with a higher partition coefficient; as the activity of a compound against mycobacteria seems to be strongly influenced by its hydrophobicity. Further, polar groups were inserted into the side chain to change the hydrophilic-lipophilic profile of the molecules. Results showed variability in the susceptibility profile of mycobacteria against the Licarin A derivatives under analysis. A number of the derivatives showed significant inhibitory activity of planktonic growth of the three strains of mycobacteria used, with even lower MIC values than those observed with reference drugs and Licarin A itself. Cytotoxicity assays showed they also have low toxicity, confirming that structural modifications to the Licarin A have made improvements to its antimycobacterial properties.

Brevipedicelones D and E, Two C-O-C Flavonoid Dimmers from the Leaves of Garcinia brevipedicellata and Anti-onchocercal Activity

A novel isoflavone-chromone flavonoid C-O-C dimmer, brevipedicelone D (1), along with one new C-O-C biflavonoid derivative, brevipedicelone E (2), were isolated from the ethyl acetate extract of the leaves of Garcinia brevipedicellata, a medicinal plant used in folk medicine in parts of Cameroon. Their structures were elucidated by extensive spectroscopic techniques, including 1D- and 2D- NMR, MS experiments, as well as comparing their spectral data with those of known analogues. Anti-onchocercal screening of 1 showed moderate inhibition of adult worm motility of Onchocerca ochengi by 60% at the highest concentration (20 µg/mL) and inhibited motility of both the juvenile worms of O. ochengi and Loa loa by 90% at this same concentration.

A Review on the Phytochemistry, Pharmacology, and Pharmacokinetics of Amentoflavone, a Naturally-Occurring Biflavonoid

Amentoflavone (C30H18O10) is a well-known biflavonoid occurring in many natural plants. This polyphenolic compound has been discovered to have some important bioactivities, including anti-inflammation, anti-oxidation, anti-diabetes, and anti-senescence effects on many important reactions in the cardiovascular and central nervous system, etc. Over 120 plants have been found to contain this bioactive component, such as Selaginellaceae, Cupressaceae, Euphorbiaceae, Podocarpaceae, and Calophyllaceae plant families. This review paper aims to profile amentoflavone on its plant sources, natural derivatives, pharmacology, and pharmacokinetics, and to highlight some existing issues and perspectives in the future.

New flavonoid C-O-C dimers and other chemical constituents from Garcinia brevipedicellata stem heartwood

The methanol extract of the stem heartwood of Garcinia brevipedicellata has furnished three new flavonoid C-O-C dimers, brevipedicilones A (6), B (8) and C (10), along with five previously reported flavonoid dimers, viz. amentoflavone (1), 4″'-O-methylamentoflavone (2), robustaflavone (3), 4'-O-methyl robustaflavone (4) and tetrahinokiflavone (5). The new structures, which are composed of flavanone-flavanonol or flavanonol-flavanonol sub-units, were established based on spectroscopic analysis including 1D and 2D NMR (1H-1H COSY, HSQC, HMBC, and NOESY) spectroscopy, and by comparing their spectral data with those reported for related compounds.

Phytochemical Constituents and Antioxidant and Antimicrobial Activity of Selected Plants Used Traditionally as a Source of Food

Many indigenous plants have also been used as a source of food and medicine in many African rural communities in the past. The study investigated the antimicrobial activity, phytochemical constituent, and antioxidant activity of selected traditional plants used traditionally as a source of food and medicine. The methanol and water extracts of different plant parts were analyzed for phytochemicals using standard phytochemical screening reagents while the broth microdilution assays were used to analyze antimicrobial activities. Alkaloids, phenols, flavonoids, saponins, tannins, and terpenes were found in one or more of the plant extracts, and all the plant extracts demonstrated scavenging activities. The back extracts of Sclerocarya birrea and the leaf extracts of Garcinia livingstonei exhibit the best antioxidant activities, while the water and methanol back extracts of S. birrea and G. livingstonei were the most active against all the tested foodborne bacteria.

In vitro antimycobacterial activity of six Cameroonian medicinal plants using microplate alamarBlue assay

OBJECTIVE/BACKGROUND

The latest incidence of tuberculosis (TB) (per 100,000 people) in Cameroon was 243.00 as of 2011. Over the past 21 years, the value for this indicator has fluctuated between 112.00 in 1990 and 320.00 in 2003. Worldwide, this incidence has also increased, bringing back TB as a reemerging disease. On the same note, resistance to anti-TB drugs has increased, urging the search for new molecules.

METHODS

This study was carried out to evaluate the antimycobacterial activity of six medicinal plants on the virulent strain, H37Rv, using the microplate alamarBlue assay. Mycobacterium tuberculosis (H37Rv strain) was incubated with decreased concentrations of six plant extracts, ranging from 250 μg/mL to 31.25 μg/mL. After 7 days of incubation at 37 °C, the effects of these plant extracts on the viability of the mycobacteria were evaluated. For each plant extract, the minimal inhibitory concentration was determined.

RESULTS

The results showed that the compounds MBC1, MBC24, MBC68, MBC81, MBC117, and MBC118 were the best candidates with minimal inhibitory concentrations of 31.25, 62.5, 125, 62.5, and 125 μg/mL, respectively.

CONCLUSION

These results confirm and validate the traditional use of these plants to treat respiratory diseases, which could be good sources and alternatives of plant metabolites for anti-TB-drug development.

Antimicrobial evaluation of plants used for the treatment of diarrhoea in a rural community in northern Maputaland, KwaZulu-Natal, South Africa

BACKGROUND

Zulu people living in the rural area of Maputaland (KwaZulu-Natal, South Africa) rely heavily on medicinal plants for the treatment of diarrhoea. Abundant availability of medicinal plants in the study area offers low cost health care, but scientific validation is needed in order to lend credibility to the traditional use against many ailments including diarrhoeal infections. With this in mind a study was designed to test the in vitro antimicrobial efficacy of 23 plant species which are used for the treatment of diarrhoea in rural Maputaland. Four 1:1 plant combinations were also evaluated to determine their interactive effects against seven diarrhoea-related bacterial pathogens.

METHODS

Minimum inhibitory concentration (MIC) assays were undertaken on dichloromethane-methanol (CH2Cl2: MeOH) and aqueous crude extracts. The following micro-organisms were selected for this study and were tested based on their association with stomach ailments and diarrhoea; Bacillus cereus (ATCC 11778), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 8739), Proteus vulgaris (ATCC 33420), Salmonella typhimurium (ATCC 14028), Shigella flexneri (ATCC 25875) and Staphylococcus aureus (ATCC 12600). The fractional inhibitory concentration index (ΣFIC) was determined for plants traditionally used in combination.

RESULTS

Shigella flexneri proved to be the most susceptible pathogen, where the organic extract of Terminalia sericea showed the most prominent noteworthy antibacterial activity (mean MIC value of 0.04 mg/mL). The aqueous extracts generally showed poorer antimicrobial activity with some exceptions i.e. Acacia burkei, Brachylaena transvaalensis against B. cereus and B. transvaalensis against S. flexneri. In the combination studies, synergy was predominant with mean (across all pathogens) ΣFIC values of 0.30 for Acanthospermum glabratum with Krauseola mosambicina; ΣFIC values of 0.46 for A. glabratum with Psidium guajava; ΣFIC values of 0.39 for B. transvaalensis with P. guajava and ΣFIC values of 0.88 (additive) for the combination of B. transvaalensis with Sclerocarya birrea.

CONCLUSION

This study provided some insight into the bacterial in vitro efficacies of plants traditionally used to treat diarrhoea by the people of Northern Maputaland. Very little connection was observed between frequency of use and efficacy. Plant combinations demonstrated favourable efficacy with mostly synergistic effects noted, lending some credibility to their use in combination.

Ethyl acetate fraction of Garcina epunctata induces apoptosis in human promyelocytic cells (HL-60) through the ROS generation and G0/G1 cell cycle arrest: a bioassay-guided approach

Number of deaths due to cancer diseases is increasing in the world. There is an urgent need to develop alternative therapeutic measures against the disease. Our study reports the cytotoxicity activity of Garcina epunctata (gutifferae) in human promyelocytic leukemia cells (HL-60) and prostate cancer cells (PC-3) was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Changes in mitochondrial membrane potential (MMP), reactive oxygen species (ROS) and morphological changes associated with apoptosis were examined by flow cytometry and Hoescht staining respectively. The results of in vitro antiproliferative screening of fractions and extract from G. epunctata indicated that three fractions inhibited the viability of PC-3 cells with IC₅₀ varied from 50 to 88 μ/ml while two fractions inhibited the proliferation of HL-60 cells with IC₅₀ range between 47.5 and 12 μg/ml. Among the entire fraction tested, Hex-EtOAc (75:25) showed cytotoxic effects on the two cell lines and EtOAc fraction was most active only HL-60 cells (12 μg/ml). Treatment of HL-60 cells with G. epunctata (20, 50, 100 μg/ml) for 24 h led to a significant dose-dependent increase in the percentage of cells in sub-G1 phase by analysis of the content of DNA in cells, and a number of apoptotic bodies containing nuclear fragments were observed in cells treated with 100 μg/ml. The EtOAc fraction of G. epunctata treatment significantly arrested HL-60 cells at the G0/G1 phase (p<0.05) and ROS was significantly elevated as well as the loss of membrane mitochondrial potential in a concentration dependant manner. The results demonstrated that the EtOAc fraction of G. epunctata inhibited the proliferation of HL-60 cells, leading to cell cycle arrest and programmed cell death, which was confirmed to occur through the mitochondrial pathway.

Preussianone, a new flavanone-chromone biflavonoid from Garcinia preussii Engl

A new flavanone-chromone biflavonoid, preussianone (1), has been isolated from the leaves of Garcinia preussii, along with four known biflavonoids. The absolute stereostructures were elucidated by chemical, spectroscopic, and chiroptical methods. The biological properties of the new biflavonoid against several bacterial strains were evaluated.