Ethanol Extract of Blighia sapida Stem Bark Show Remarkable Prophylactic Activity in Experimental Plasmodium berghei-Infected Mice

Senna occidentalis (L.) Link root extract inhibits Plasmodium growth in vitro and in mice

BACKGROUND

Senna occidentalis (L.) Link has been used worldwide in traditional treatment of many diseases and conditions including snakebite. In Kenya, a decoction from the plant roots taken orally, is used as a cure for malaria. Several studies have demonstrated that extracts from the plant possess antiplasmodial activity, in vitro. However, the safety and curative potency of the plant root against established malaria infection is yet to be scientifically validated, in vivo. On the other hand, there are reports on variation in bioactivity of extracts obtained from this plant species, depending on the plant part used and place of origin among other factors. In this study, we demonstrated the antiplasmodial activity of Senna occidentalis roots extract in vitro, and in mice.

METHODS

Methanol, ethyl acetate, chloroform, hexane and water extracts of S. occidentalis root were tested for in vitro antiplasmodial activity against Plasmodium falciparum, strain 3D7. Cytotoxicity of the most active solvent extracts was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the curative potency in Plasmodium berghei infected mice evaluated by Rane's test.

RESULTS

All of the solvent extracts tested in this study inhibited the propagation of P. falciparum, strain 3D7, in vitro, with polar extracts being more active than non-polar ones. Methanolic extracts had the highest activity (IC50 = 1.76) while hexane extract displayed the lowest activity (IC50 = 18.47). At the tested concentrations, methanolic and aqueous extracts exhibited high selectivity index against P. falciparum strain 3D7 (SI > 10) in the cytotoxicity assay. Further, the extracts significantly suppressed the propagation of P. berghei parasites (P < 0.05) in vivo and increased the survival time of the infected mice (P < 0.0001).

CONCLUSIONS

Senna occidentalis (L.) Link root extract inhibits the propagation of malaria parasites in vitro and in BALB/c mice.

Antiplasmodial evaluation of aqueous extract of Blighia sapida K.D. Koenig leaves in Plasmodium berghei (NK65)-infected mice

Background

The study was designed to screen aqueous extract of Bilghia sapida leaves for its phytochemical constituents, in vivo antiplasmodial activity and biochemical changes in Plasmodium berghei (NK65)-infected female mice. Phytochemical screening was done using standard methods. In the acute toxicity test, three groups of mice received 1000, 2000 and 3000 mg/Kg/day of the extract respectively, and were observed for signs of toxicity, especially mortality for 24 h. Forty-eight mice were assigned into six groups of eight animals each. The uninfected group A (control) was administered distilled water, while groups B, C, D, E and F were inoculated intraperitoneally with about 107 parasitized erythrocytes and received distilled water, chloroquine (5 mg/Kg/day), 125, 250 and 500 mg/Kg/day of extract, respectively. The antiplasmodial activity was evaluated using Peter’s 4 days suppressive test. Haematological indices, selected biochemical parameters and liver histology were evaluated.

Results

Screening revealed the presence of six phytochemicals in the aqueous extract of B. sapida leaves. Median lethal dose of the extract is > 5,000 mg/Kg/day. The aqueous extract of the leaves significantly (P < 0.05) reduced the level of parasitaemia dose-dependently with chemosuppression of 74.09% at 500 mg/Kg/day. The extract significantly (P < 0.05) prevented P. berghei infection-associated reduction in red blood cell indices. The significant (P < 0.05) P. berghei-induced alterations in liver function indices were improved in extract-treated mice. There were no visible lesions in the livers of animals that received 125 mg/Kg/day of extract.

Conclusion

The aqueous extract of B. sapida leaves has in vivo antiplasmodial activity and justifies its folkloric use in malarial treatment.

Antiplasmodial, antimalarial activities and toxicity of African medicinal plants: a systematic review of literature

BACKGROUND

Malaria still constitutes a major public health menace, especially in tropical and subtropical countries. Close to half a million people mainly children in Africa, die every year from the disease. With the rising resistance to frontline drugs (artemisinin-based combinations), there is a need to accelerate the discovery and development of newer anti-malarial drugs. A systematic review was conducted to identify the African medicinal plants with significant antiplasmodial and/or anti-malarial activity, toxicity, as wells as assessing the variation in their activity between study designs (in vitro and in vivo).

METHODS

Key health-related databases including Google Scholar, PubMed, PubMed Central, and Science Direct were searched for relevant literature on the antiplasmodial and anti-malarial activities of African medicinal plants.

RESULTS

In total, 200 research articles were identified, a majority of which were studies conducted in Nigeria. The selected research articles constituted 722 independent experiments evaluating 502 plant species. Of the 722 studies, 81.9%, 12.4%, and 5.5% were in vitro, in vivo, and combined in vitro and in vivo, respectively. The most frequently investigated plant species were Azadirachta indica, Zanthoxylum chalybeum, Picrilima nitida, and Nauclea latifolia meanwhile Fabaceae, Euphorbiaceae, Annonaceae, Rubiaceae, Rutaceae, Meliaceae, and Lamiaceae were the most frequently investigated plant families. Overall, 248 (34.3%), 241 (33.4%), and 233 (32.3%) of the studies reported very good, good, and moderate activity, respectively. Alchornea cordifolia, Flueggea virosa, Cryptolepis sanguinolenta, Zanthoxylum chalybeum, and Maytenus senegalensis gave consistently very good activity across the different studies. In all, only 31 (4.3%) of studies involved pure compounds and these had significantly (p = 0.044) higher antiplasmodial activity relative to crude extracts. Out of the 198 plant species tested for toxicity, 52 (26.3%) demonstrated some degree of toxicity, with toxicity most frequently reported with Azadirachta indica and Vernonia amygdalina. These species were equally the most frequently inactive plants reported. The leaves were the most frequently reported toxic part of plants used. Furthermore, toxicity was observed to decrease with increasing antiplasmodial activity.

CONCLUSIONS

Although there are many indigenous plants with considerable antiplasmodial and anti-malarial activity, the progress in the development of new anti-malarial drugs from African medicinal plants is still slothful, with only one clinical trial with Cochlospermum planchonii (Bixaceae) conducted to date. There is, therefore, the need to scale up anti-malarial drug discovery in the African region.

Photosynthetically Controlled Spirulina, but Not Solar Spirulina, Inhibits TNF-α Secretion: Potential Implications for COVID-19-Related Cytokine Storm Therapy

An array of infections, including the novel coronavirus (SARS-CoV-2), trigger macrophage activation syndrome (MAS) and subsequently hypercytokinemia, commonly referred to as a cytokine storm (CS). It is postulated that CS is mainly responsible for critical COVID-19 cases, including acute respiratory distress syndrome (ARDS). Recognizing the therapeutic potential of Spirulina blue-green algae (Arthrospira platensis), in this in vitro stimulation study, LPS-activated macrophages and monocytes were treated with aqueous extracts of Spirulina, cultivated in either natural or controlled light conditions. We report that an extract of photosynthetically controlled Spirulina (LED Spirulina), at a concentration of 0.1 µg/mL, decreases macrophage and monocyte-induced TNF-α secretion levels by over 70% and 40%, respectively. We propose prompt in vivo studies in animal models and human subjects to determine the putative effectiveness of a natural, algae-based treatment for viral CS and ARDS, and explore the potential of a novel anti-TNF-α therapy.

Blighia sapida K.D. Koenig: A review on its phytochemistry, pharmacological and nutritional properties

ETHNOPHARMACOLOGICAL RELEVANCE

Ackee plant (Blighia sapida K. D. Koenig) (Sapindaceae) is used in Sub-Saharan Africa (where it has its origin) and in different parts of the world (The Caribbean, North and South America, Europe). Traditionally it is used to manage numerous ailments like backache, constipation, cancer, fever in young children, gonorrhea, dysentery, psychosis, hernia, stomach ache, malaria, rheumatism, typhoid etc. It is also used as a cosmetic and food source. The fruit aril is the main constituent of the Jamaican National Dish. This review summarizes its phytochemistry, nutritional properties, ethnobotany and pharmacology. The need to gather up to date information on this plant, to facilitate in vivo and in vitro investigations for verification of some of the local claims necessitated this review.

MATERIALS AND METHODS

A literature search was performed on Ackee using ethno botanical text books and scientific databases such as PubMed, Scopus, EBSCO, Science-direct, Google, Google Scholar and other web sources like records from PROTA, PROSEA, JSTOR and Botanical Dermatology Database.

RESULTS AND DISCUSSION

This review highlights the traditional uses of parts of the Ackee plant: the bark, the leaves, capsules, roots and seeds. They are used in the management of diverse disease conditions such as diarrhoea, conjunctivitis, fever, internal hemorrhage, dysentery, cutaneous skin infections, and bacterial infections amongst others. Only nineteen compounds have been reportedly isolated from the parts of B. sapida; Alkaloids, quinines, polyphenols, and steroids, their glycosides, sesquiterpenes and triterpenes. Some of the plant extracts and its isolated compounds showed anticancer, antimicrobial, antidiarrheal, antioxidant and hypoglycemic activities both in vitro and in vivo. The seed/leaves have also been used as insect repellants and the leaves have been reported to have lethal effects on larvae of various mosquitoes' species. The oil contains a lot of nutrients and may be considered for edible consumption after safety has been confirmed. Hypoglycin A and the less malignant hypoglycin B are found in the unripe aril of Ackee and consumption results in hypoglycemia, vomiting, gluconeogenesis disruption which can result in coma and death. The untapped economic potential of its fruits is glaring in West Africa countries.

CONCLUSION

Though B.sapida has been put to enormous traditional use, the pharmacological studies conducted are not sufficient, most studies are either in-vivo or in-vitro. More work is required (well-designed pharmacological tests, randomized clinical trials) to evaluate these medicinal claims. This review provides a basis for future research. The isolation of more compounds,detailed pharmacological investigations, exploration of food use and detoxification techniques are key areas to investigate.