Cognitive-Enhancing, Ex Vivo Antilipid Peroxidation and Qualitative Phytochemical Evaluation of the Aqueous and Methanolic Stem Bark Extracts of Lonchocarpus eriocalyx (Harms.)

A Comprehensive Review of Ethnomedicinal Uses, Phytochemistry, Pharmacology, and Toxicity of Prunus africana (Hook. F.) Kalkman from Africa

Prunus africana, a widely utilized medicinal plant in various African ethnic communities, continues to hold significant importance in traditional healing practices. Research has identified phytochemical compounds in this plant, exhibiting diverse pharmacological activities that offer potential for pharmaceutical development. Notably, P. africana is employed in treating various ailments such as wounds, diabetes mellitus, malaria, benign prostatic hyperplasia, chest pain, and prostate cancer. Its pharmacological properties are attributed to a spectrum of bioactive compounds, including tannins, saponins, alkaloids, flavonoids, terpenoids, phytosterols, and fatty acids. Multiple studies have documented the anti-inflammatory, antimicrobial, antiandrogenic, antiangiogenic, antioxidant, antidipeptidyl peptidase-4 activity, analgesic, and astringent properties of P. africana extracts. This review offers a comprehensive compilation of ethnomedicinal applications, phytochemical composition, pharmacological effects, and toxicity assessments of P. africana, serving as a foundation for future preclinical and clinical investigations. By understanding its traditional uses and chemical constituents, researchers can target specific medical conditions with greater precision, potentially expediting the development of safe and effective pharmaceuticals. Moreover, toxicity assessments provide crucial insights into the safety profile of P. africana extracts, ensuring the development of safe pharmaceuticals to treat various diseases.

Acute oral toxicity, cognitive-enhancing and anti-lipid peroxidation efficacy, and qualitative phytochemistry of the aqueous aerial part extract of Launaea cornuta (Hochst. ex. Oliv. &Hiern) C. Jeffrey

At present, there is no cure for dementia or its related cognitive impairments. Available treatments only provide symptomatic relief and do not alter the disease's progression and they suffer serious drawbacks limiting their clinical use, hence the need for alternative therapies. Although Launaea cornuta has been used traditionally to treat cognitive deficits, its pharmacological efficacy and safety have not been empirically validated, prompting this study. Acute oral toxicity of the extract was examined in Swiss albino mice using the up-and-down procedure described by the Organisation for Economic Cooperation and Development guideline number 425. The Morris water maze technique was adopted in assessing cognitive-enhancing effects of the extract in ketamine-induced cognitive-impaired mice. The malondialdehyde concentrations in the whole brain of experimental mice involved in the MWM experiment were measured to determine the extract's anti-lipid peroxidation efficacy. Qualitative phytochemical screening of the extract was performed using standard procedures. Our results showed that the test extract was safe and did not cause any clinical signs of acute oral toxicity in mice at all doses (LD50 > 2000 mg/kg BW). Moreover, the extract significantly improved cognitive function in ketamine-induced cognitive-impaired mice in a dose-dependent manner, as indicated by reduced escape latency, navigation distance, and longer latency in the target quadrant during the probe trial. The extract also significantly reduced malondialdehyde concentrations in mice in a dose-dependent manner, demonstrating its antioxidative stress efficacy. The studied extract contained various phytochemicals associated with cognitive enhancement and antioxidant efficacy, among other pharmacologic effects. Further empirical studies are needed to determine and characterise the extract's specific cognitive-enhancing compounds, specific mechanisms of action, and complete toxicity profiles.

Phytochemical Screening, Toxic Effects, and Antimicrobial Activity Studies of Digitaria abyssinica (Hochst. ex A.Rich.) Stapf (Poaceae) Rhizome Extracts against Selected Uropathogenic Microorganisms

In Kenya, the D. abyssinica rhizome's decoction is traditionally used to treat urinary tract infections (UTIs), mainly gonorrhea and candidiasis. UTIs are the most severe public health problems that affect over one hundred and fifty million people worldwide annually. They are caused by a wide range of microorganisms where Escherichia coli is known to be the main causative pathogen. Medicinal plants are used in traditional Kenya set up for treatment and most recently as an alternative source of treatment for UTIs due to the increased cost of treatment and many challenges experienced with antibiotic therapy. The current study is designed to investigate the phytochemical composition, acute oral toxicity, and antimicrobial activity of Digitaria abyssinica rhizome extracts against Staphylococcus aureus, Escherichia coli, Neisseria gonorrhea, and Candida albicans. The rhizomes of D. abyssinica were obtained, dried, ground, and extracted using water and organic solvents. The phytochemical assay was carried out using standard phytochemical screening methods. Single-dose toxicity studies were done to determine LD₅₀ while disk diffusion and microbroth dilution techniques were used to determine antimicrobial activity. Results revealed that saponins, phenolics, alkaloids, cardiac glycosides, tannins, flavonoids, steroids, and terpenes were present in the powder, aqueous, methanol, and dichloromethane : methanol extracts. All the extracts had an LD₅₀ of above 2,000 mg/kg of body weight and there was no observation of behavioral changes. Also, the aqueous and methanol extracts revealed antifungal activity against Candida albicans with the lowest average minimum zone of inhibition at MIC of 31.25 mg/ml. The study did not reveal antibacterial activity for any extract against the studied uropathogenic bacteria, Staphylococcus aureus, Escherichia coli, and Neisseria gonorrhoeae. The results from the current study suggested that D. abyssinica rhizome aqueous and methanol extracts have potential antifungal activity against C. albicans, thus validating the folklore of its use to treat candidiasis.

Antioxidant, Antimicrobial, and Kinetic Studies of Β-Cyclodextrin Crosslinked with Lignin for Drug Delivery

β-Cyclodextrin was attached to lignin/lignin crosslinked by epichlorohydrin and served as a drug delivery matrix. Ketoconazole and piroxicam were added into the polymeric matrix as antifungal and anti-inflammatory agents, respectively. The percentage of drug retained ranged from 48.4% to 58.4% for ketoconazole and piroxicam, respectively. It was found that their tensile strengths increased with decreasing particle size, ranging between 59% and 71% for lignin crosslinked with β-cyclodextrin base matrix (LCD). Depending on the polymeric matrix, the drug release kinetics fit well in the Korsmeyer-Peppas model, with or without Fickian diffusion. From the materials based on the mixture of epoxidized lignin and β-cyclodextrin, the medicines were released more slowly (the release rate constant presents lower values ranging between 1.117 and 1.783), as compared with those comprising LCD (2.210-4.824). The materials were also demonstrated to have antimicrobial activity. The antioxidant activity of LCD loaded with piroxicam was found to be 23.9% greater than that of the base matrix (LCD). These findings could be useful towards β-cyclodextrin attached to lignin formulation development of drug carriers with antioxidant activity.

Evaluation of Uterotonic Activity, Acute Oral Toxicity, and Phytochemical Composition of Uvariodendron anisatum Verdc. Root Extracts

Over 80% of cultural societies in low-income countries use plant preparations in traditional medicine with unknown potency and safety profiles. Uvariodendron anisatum root extracts are used by some Kenyan herbalists. However, the claims of the plant to remove retained placenta during birth have remained uninvestigated. Therefore, the current study evaluated its uterotonic activities. Acute toxicity in Wistar rats and the phytochemical composition of the plant were also studied. The plant was collected from Embu County in Kenya. The water and ethanol extracts were prepared by maceration. Uterine strips were isolated from primed mature female Wistar rats and used to study the uterotonic activities of the extracts. De Jalon's solution and oxytocin were used as negative and positive controls, respectively. Acute oral toxicity studies were done following the OECD 423 guideline and phytochemical screening were based on standard phytochemical procedures. The study met all the approval requirements before commencement. Data obtained from the uterotonic activity were analysed by using GraphPad Prism Version 8.0.1 software and expressed as a percentage increase or decrease of mean as mean ± SEM relative to the controls. The findings of acute oral toxicity were expressed using LD₅₀. Additionally, the phytochemical components of the U. anisatum were tabulated. The uterotonic effect of Uvariodendron anisatum root water extract was higher than that of ethanol extract. A single dose of the Uvariodendron anisatum root water extract at 2000 mg/kg did not cause mortality in the tested Wistar rats. Besides, there were no changes in hematological and biochemical parameters. The extracts did not reveal changes in the gross morphology of the liver, kidney, heart, and lung of the tested Wistar rats. However, the histopathological studies of Uvariodendron anisatum root water extracts exhibited toxicity in the liver, kidney, and lung tissues of Wistar rats at a concentration of 2000 mg/kg. Alkaloids, glycosides, saponins, phytosterols, terpenes, proteins, phenols, and oils were recorded in Uvariodendron anisatum. The findings from this study provided scientific evidence which is useful in validating the use of Uvariodendron anisatum extracts in the stimulation of the uterus during birth.

Subacute Toxicity Effects of the Aqueous Shoot Extract of Yushania alpina (K. Schum.) W.C.Lin in Sprague Dawley Rats: An Appraisal of Its Safety in Ethnomedicinal Usage

Plant-based medicines have effectively managed several ailments in humans and animals since prehistoric times. However, the pharmacologic efficacy and safety of many plants currently used in traditional medicine have not been explored empirically, which raises serious public health concerns, derailing further research and their integration into the conventional healthcare system. Despite the longstanding ethnomedicinal usage of Yushania alpina shoot extract to treat inflammation, microbial infections, and diarrhoea, among other diseases, there is insufficient scientific data to appraise its toxicity profile and safety. Accordingly, we investigated the subacute toxicity of the aqueous shoot extract of Y. alpina in Sprague Dawley rats (both sexes) for 28 days based on the Organisation for Economic Cooperation and Development guideline 407. In this study, all the experimental rats treated orally with 40 mg/Kg BW, 200 mg/Kg BW, and 1000 mg/Kg BW of the aqueous shoot extract of Y. alpina remained normal, like the control group rats, and did not show any clinical signs of subacute toxicity, and no morbidity or mortality was recorded. Besides, the weekly body weight gains and the haematological and biochemical parameters of experimental rats orally administered with the studied plant extract at the tested doses and in the control group were comparable (P > 0.05). No pathologic alterations in internal organs were observed following necroscopy. Further, the differences in weights of the liver, kidney, and spleen of experimental rats which were subacutely treated with the studied plant extract and the control rats were insignificant (P > 0.05). Moreover, no histopathological changes were observed in tissue sections of the liver, kidney, and spleen obtained from all the experimental rats. Our findings demonstrate that the aqueous shoot extract of Y. alpina may be safe as it does not elicit subacute toxicity in Sprague Dawley rats. Further toxicological and pharmacological studies using other model animals and in clinical setups are encouraged to fully appraise the efficacy and safety of the studied plant extract.

Antidiarrheal, antimicrobial, and toxic effects of the aqueous and methanolic leaf and fruit extracts of Cucumis dipsaceus (Ehrenb. Ex Spach.)

Introduction: Cucumis dipsaceus is used to treat diarrhoea, microbial infections, among other diseases across the world; however, there is insufficient empirical data to validate its efficacy, toxicity, and safety. Accordingly, we investigated the antidiarrheal, antimicrobial, and toxic effects of the aqueous and methanolic leaf and fruit extracts of C. dipsaceus.Methods: Antidiarrheal activities of the aqueous and methanolic leaf and fruit extracts of C. dipsaceus were investigated using the castor oil-induced diarrhoea technique in a Wistar rat model. The disk diffusion and broth microdilution methods were adopted to determine the antimicrobial activities of the studied plant extracts. The acute oral toxicity effects of the studied plant extracts were investigated in Wistar rats according to the Organisation for Economic Co-operation and Development (OECD) guidelines.Results: The aqueous and methanolic leaf and fruit extracts of C. dipsaceus significantly (P < 0.05) inhibited diarrhoea in a dose-dependent manner in experimental rats. Besides, the studied extracts significantly (P < 0.05) inhibited the growth of Salmonella enteritidis, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Candida albicans in varying degrees, as depicted by their growth inhibition zones (>6.00 mm) and minimum inhibitory concentrations (MICs <1000 μg/mL). Moreover, the studied extracts did not cause any observable acute oral toxicity effects in the experimental rats across the 14-day experimental period.Conclusion: The aqueous and methanolic leaf and fruit extracts of C. dipsaceus present a potential source of safe and efficacious lead compounds for developing antidiarrheal and antimicrobial therapies.

Anti-inflammatory, Analgesic, and Cytotoxic Effects of The Phytexponent: A Polyherbal Formulation

The Phytexponent is used to treat pain and inflammation in complementary and alternative medicine practices; however, empirical data supporting its pharmacological efficacy and safety is scanty, hence the present study. We used the carrageenan-induced paw oedema and the acetic acid-induced writhing techniques to determine the anti-inflammatory and analgesic efficacies, respectively, of the Phytexponent in Swiss albino mice models. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay technique was used to investigate the in vitro cytotoxic effects of the Phytexponent in the Vero E6 cell line. The Phytexponent exerted significant (P < .05) anti-inflammatory effects in the carrageenan-induced paw oedema mouse model in a dose- and time-dependent manner, with significantly higher efficacy at 250 mg/Kg BW, than indomethacin (4 mg/Kg BW), in the first, second, and third hour (P < .05). Besides, the Phytexponent significantly reduced the acetic acid-induced writhing frequency in mice (P < .05), in a dose-dependent manner, depicting its analgesic efficacy. Notably, the Phytexponent (at doses: 125 mg/Kg BW and 250 mg/Kg BW) exhibited significantly higher analgesic efficacy than the Indomethacin (P<.05). Moreover, the Phytexponent was not cytotoxic to Vero E6 cells (CC₅₀ >1000 µg/ml) compared to cyclophosphamide (CC₅₀ = 2.48 µg/ml). Thus, the Phytexponent has significant in vivo anti-inflammatory and analgesic efficacy in mice models and is not cytotoxic to Vero E6 cell line, depicting its therapeutic potential upon further empirical investigation.

Antioxidant, Anti-Inflammatory, Acute Oral Toxicity, and Qualitative Phytochemistry of The Aqueous Root Extract of Launaea cornuta (Hochst. Ex Oliv. & Hiern.)

The root and leaf extracts of Launaea cornuta have been locally used in traditional medicine for decades to manage inflammatory conditions and other oxidative-stress-related syndromes; however, their pharmacologic efficacy has not been scientifically investigated and validated. Accordingly, we investigated the in vitro antioxidant activity, anti-inflammatory (in vitro, ex vivo, and in vivo) efficacy, acute oral toxicity, and qualitative phytochemical composition of the aqueous root extract of L. cornuta. The ferric-reducing antioxidant power (FRAP) and the 2,2-diphenyl-2-pycrylhydrazyl (DPPH) radical scavenging test methods were used to determine the studied plant extract’s antioxidant activity. Besides, the anti-inflammatory efficacy of the studied plant extract was investigated using in vitro (anti-proteinase and protein denaturation), ex vivo (membrane stabilization), and in vivo (carrageenan-induced paw oedema in Swiss albino mice) methods. The studied plant extract demonstrated significant in vitro antioxidant effects, which were evidenced by higher DPPH radical scavenging and FRAP activities, in a concentration-dependent manner (p < 0.05). Generally, the studied plant extract exhibited significant in vitro, ex vivo, and in vivo anti-inflammatory efficacy, respectively, and in a concentration/dose-dependent manner compared with respective controls (p < 0.05). Moreover, the studied plant extract did not cause any observable signs of acute oral toxicity, even at the cut-off dose of 2000 mg/Kg BW (LD₅₀ > 2000 mg/Kg BW), and was thus considered safe. Additionally, qualitative phytochemistry revealed the presence of various antioxidant- and anti-inflammatory-associated phytochemicals, which were deemed responsible for the reported pharmacologic efficacy. Further studies to characterise bioactive molecules and their mode(s) of pharmacologic efficacy are encouraged.

Ethnobotanical Documentation, Phytochemical Screening, and Cytotoxicity Evaluation of Medicinal Plants Used to Manage Snakebite Envenomation in Mwingi West Subcounty, Kenya

Snakebite envenomation (SBE) is a life-threatening global public health problem affecting over 2.7 million persons annually, with a bigger burden lying in the developing world. Despite the successful management of SBE by antivenom therapy in conventional medicine, it is of low efficacy due to the diverse venom composition across snake types, which limits its usefulness. As a result, inhabitants of the sub-Sahara region, where SBE incidence is high, utilise medicinal plants as an alternative remedy for SBE. However, most plants have not been ethnobotanically documented and validated empirically and hence this study is needed. An ethnobotanical survey to document medicinal plants used to manage SBE in Migwani ward, Mwingi West Subcounty, Kitui County, was conducted between January and February, 2021. Ethnobotanical data were collected from 45 purposefully sampled respondents from Migwani ward using semistructured questionnaires, field walks, and oral interviews. In this study, 14 medicinal plants which are used to manage SBE were documented. Four plants with the highest Relative Frequency of Citation (RFC) (Entada leptostachya Harms-stem bark (0.58), Senna singueana-roots (0.53), Securidaca longipendunculata-roots (0.36), and Strychnos henningsii-stem bark (0.46)) were selected and extracted using water, methanol, and dichloromethane according to the standard procedures. Qualitative phytochemical analysis of the plant extracts and their cytotoxic effects on brine shrimp nauplii (brine shrimp lethality assay) was conducted according to the standard techniques. Qualitative phytochemical screening revealed the presence of anti-SBE-associated phytochemicals, such as alkaloids, saponins, tannins, phenols, and flavonoids, in the aqueous and methanolic extracts of the studied plant extracts. However, the tested phytochemicals were not detected in dichloromethane extracts of all the studied extracts. The anti-SBE effects of the documented plants could be attributable to these associated bioactive phytocompounds, which are synthesized by the studied plants and transfered to humans when consumed. Furthermore, the aqueous and methanolic extracts of Entada leptostachya and Senna singueana had high LC₅₀ of >1000 µg/ml and were considered noncytotoxic. However, Securidaca longipendunculata had an LC₅₀ of <1000 µg/ml and was considered slightly cytotoxic. Further empirical investigations to characterise the bioactive phytochemicals and their safety should be done.

In vivo anti-inflammatory, anti-nociceptive, and in vitro antioxidant efficacy, and acute oral toxicity effects of the aqueous and methanolic stem bark extracts of Lonchocarpus eriocalyx (Harms.)

Oxidative stress causes and drives many agonising inflammatory conditions, which cause disability, financial burden, and emotional stress. The current anti-inflammatory, analgesic, and antioxidant agents are associated with adverse effects, inaccessibility, high costs, and low efficacies, thereby warranting the need for alternatives, especially from natural sources. Lonchocarpus eriocalyx plant is traditionally used in Kenyan communities to treat various inflammatory and oxidative stress-associated diseases; however, its pharmacologic efficacy and safety have not been empirically validated, hence this study. The in vivo antiinflamatory and antinociceptive efficacy of the aqueous and methanolic stem bark extracts of L. eriocalyx were determined using the xylene-induced ear oedema, and the acetic acid-induced writhing techniques, respectively, in experimental mice. Also, in vitro antioxidant activities of the studied plant extracts were investigated using the Thiobarbituric acid test for lipid peroxidation, 1, 1-diphenyl -2-picrylhydrazyl (DPPH), and Ferric reducing antioxidant power standard assay methods. Moreover, the studied extracts' acute oral toxicity effects were investigated according to the Organisation for Economic Corporation and Development (OECD) guidelines. The studied plant extracts showed significant dose-dependent inhibitions of oedema and writhing, depicting their anti-inflammatory and antinociceptive efficacy. Besides, the extracts revealed significant inhibitions of in vitro lipid peroxidation in varying degrees. Notably, the extracts demonstrated very strong DPPH radical scavenging and ferric-reducing antioxidant efficacies. Furthermore, the two studied plant extracts did not elicit acute oral toxicity, with LD50 values of >2000 mg/kg BW, hence were considered safe. The anti-inflammatory, antinociceptive, and in vitro antioxidant efficacies of these extracts were attributed to antioxidant phytocompounds with diverse pharmacologic effects, especially through the amelioration of oxidative stress. Further studies on the anti-inflammatory, antinociceptive and antioxidant mechanism(s) and isolation and characterisation of responsible compounds are encouraged to spur the development of affordable, accessible, safe, and efficacious drugs.