Safety assessment of crude aqueous methanol extract of Annona senegalensis stem bark: acute and sub-chronic toxicity studies.

Annona senegalensis Pers., (wild custard apple), is a shrub used traditionally to treat respiratory and skin diseases. Previous studies have demonstrated its anti-malaria, anti-snake envenomation and anti-cancer activities. However, its toxicological profile remains limited, particularly in male and female animals. This study aims to evaluate the safety of crude aqueous methanol extract of Annona senegalensis stem bark (AMEAS) through acute and sub-chronic toxicity studies. The stem bark of A. senegalensis was collected, air-dried, pulverized, and extracted using 70% methanol. Phytochemical screening, elemental analysis, and acute toxicity evaluation were carried out on AMEAS. Sub-chronic toxicity study was conducted on Wistar rats of both sexes at different doses administered orally for 28 days. Elemental analysis revealed the presence of heavy metals and essential mineral elements with the highest contents being calcium (59.88%) and potassium (25.39%). Acute toxicity testing showed no mortality up to 5000 mg/kg, suggesting an LD50 greater than 5000 mg/kg. In the sub-chronic toxicity study, no mortality or significant harmful effects were observed. The blood glucose decreased from 13.68 mMol/L at 250 mg/kg to 10.71 mMol/L at 1000 mg/kg, much lower than the distilled water group (17.06 mMol/L). In conclusion, the extract appeared to be well-tolerated, with no obvious adverse effects. AMEAS is rich in Calcium (Ca) and potassium (K). It has been shown to have LD50 greater than 5000 mg/kg and is assumed to be safe. On repeated use, AMEAS may cause hypoglycemia and weight loss which may be useful in managing diabetes and obesity respectively.

Studies on neurobehavioural properties of Caralluma dalzielii N.E Br. aqueous aerial parts extract in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Caralluma dalzielii (Asclepiadiaceae) is a shrub used in folkloric medicine to treat epilepsy, pain and infertility in sub-Saharan Africa. Previous studies demonstrated its analgesic, antiulcer, anticonvulsant, and anti-inflammatory activities. AIM: This study aimed to determine the neurobehavioural properties of Caralluma dalzielii aqueous aerial parts extract (CDAE) in mice using standard experimental models. MATERIALS AND METHODS: Neurobehavioural activities of CDAE were evaluated (100, 200, and 400 mg/kg) in Swiss Albino mice using the beam walk, staircase, hole board, object recognition, open field assay, Y-maze and forced swimming tests. Phytochemical constituents were analysed using GC-MS. RESULTS: CDAE significantly increased the mean number of head dips, recognition index and spontaneous alternation in hole board (14.03 at 400 mg/kg and 6.01 in distilled water group; p < 0.05), object recognition (68.16% at 400 mg/kg compared with 51.66% of distilled water group) and Y maze (9.16 at 400 mg/kg as against 4.66 of distilled water group; p < 0.05) tests respectively. It decreased the rearing counts as well as the peripheral and central square crossing in the staircase (4.2 at 400 mg/kg as against 7.87 of the distilled water group; p < 0.05) and open field tests (central, 0.81; peripheral, 1.66 at 400 mg/kg as against central, 5.23; peripheral 11.83 of the distilled water control group; p < 0.05), respectively. There were no significant effects on beam walk assays and forced swim tests. The GC-MS analysis identified a hundred compounds in CDAE. Some compounds which have been reported to possess neurobehavioural activity that were identified include 3,5-Dimethylpyrazole, 2-Amino-5-methylbenzoic acid, Acetophenone, and Tetrahydropyran. CONCLUSION: CDAE demonstrated anxiolytic, anti-hyperactivity, and memory-improving effects in mice. The extract may possess GABAergic and glutamatergic properties. More studies are needed to confirm this. Isolation of the bioactive compounds is currently ongoing to unravel the bioactive constituents present in C. dalzielii extract.

Toxicity assessment of methanol extract of Parinari curatellifolia Planch ex. Benth.

Parinari curatellifolia is mostly employed in the treatments of leukemia, anemia and malaria. The study was to determine the hematological, biochemical and histopathological effects of methanol stem bark extract of Parinari curatellifolia (PCME) on liver and kidney of adult female Wistar rats. The oral acute (Lorke's method) and sub-chronic toxicity of PCME were evaluate. Adult female Wistar rats were grouped into group I (n=6), normal control (5mL/kg of distilled water) and groups II-IV (100, 200 and 400mg/kg/day of PCME, n=6 each) for 30 days. On 31st day, biochemical, hematological and histopathological parameters were assessed. The LD50 was found greater than 5000mg/kg. In hematological parameters, RBC showed an increase in the treatment groups, however, the increment was not significant. HCT, PLT, MCH and MCHC levels were significantly increased (p<0.05) while WBC levels in all PCME groups were reduced (p<0.05). Amongst the liver biochemical parameters, only the ALP activity was significantly (p<0.05) raised. In kidney biochemical parameters, serum potassium and chloride were significantly (p<0.05) reduced. Histopathological findings on the liver showed mild infiltrating leukocytes, vascular congestion and piece meal necrosis compared to the normal anatomic features while that of the kidney appeared normal. In conclusion, PCME may be slightly toxic to the liver on repeated administration.

Computational assessment of chemicals from Morinda citrifolia as potential inhibitors of B-Raf kinase in hepatocellular carcinoma treatment.

Hepatocellular carcinoma (HCC) is a tumour pathology that lacks specific treatment and is predominantly resistant to chemotherapy. The inhibitory activity of Morinda citrifolia, an evergreen tree commonly called Noni, against various carcinomas especially HCC is widely acclaimed. This study was to assess the phytochemical constituents of the plant for inhibitory activity against B-Raf kinase (3C4C) in order to design drugs for HCC treatment. Molecular docking, pharmacophore modelling, induced-fit docking, molecular dynamics (MD) simulations and ADMET predictions were the computational techniques employed in this study to detect potential inhibitors of B-Raf kinase from 135 compounds of Morinda citrifolia. Soranjidiol, Thiamine, Lucidin, 2-Methyl-1,3,5-Trihydroxyanthraquinone and Rubiadin were the five top-scoring compounds ranging from -8.39 to -8.22 kcal/mol, however, the standard ligand, PLX4720, scored -11.26 kcal/mol. The five compounds, like PLX4720 demonstrated hydrogen bond interactions with active site amino acid residues such as GLN 530, CYS 532 and ASP 594. The main energy contributor to the interactions between the compounds and B-Raf kinase were pi-stacking, hydrogen bond, van der Waals and covalent energy. Better docking scores obtained in the induced-fit docking further validates the inhibitory potential of the Soranjidiol against the flexible protein. In MD simulations, Soranjidiol revealed good stability in the active site of the protein since significant conformational changes were not evident. These five compounds, unlike the standard compound, demonstrated adequate druglike properties and good safety profiles. Therefore, further studies should be undertaken so as to develop them into drugs against HCC.Communicated by Ramaswamy H. Sarma.

A Computational Approach to Elucidate the Interactions of Chemicals From Artemisia annua Targeted Toward SARS-CoV-2 Main Protease Inhibition for COVID-19 Treatment.

The inhibitory potential of Artemisia annua, a well-known antimalarial herb, against several viruses, including the coronavirus, is increasingly gaining recognition. The plant extract has shown significant activity against both the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and the novel SARS-CoV-2 that is currently ravaging the world. It is therefore necessary to evaluate individual chemicals of the plant for inhibitory potential against SARS-CoV-2 for the purpose of designing drugs for the treatment of COVID-19. In this study, we employed computational techniques comprising molecular docking, binding free energy calculations, pharmacophore modeling, induced-fit docking, molecular dynamics simulation, and ADMET predictions to identify potential inhibitors of the SARS-CoV-2 main protease (Mpro) from 168 bioactive compounds of Artemisia annua. Rhamnocitrin, isokaempferide, kaempferol, quercimeritrin, apigenin, penduletin, isoquercitrin, astragalin, luteolin-7-glucoside, and isorhamnetin were ranked the highest, with docking scores ranging from -7.84 to -7.15 kcal/mol compared with the -6.59 kcal/mol demonstrated by the standard ligand. Rhamnocitrin, Isokaempferide, and kaempferol, like the standard ligand, interacted with important active site amino acid residues like HIS 41, CYS 145, ASN 142, and GLU 166, among others. Rhamnocitrin demonstrated good stability in the active site of the protein as there were no significant conformational changes during the simulation process. These compounds also possess acceptable druglike properties and a good safety profile. Hence, they could be considered for experimental studies and further development of drugs against COVID-19.

Acute and sub-acute toxicity of aqueous extract of aerial parts of Caralluma dalzielii N. E. Brown in mice and rats.

Caralluma dalzielii N. E. Brown (Asclepiadaceae) is a cactus-like shaped shrub widely used in traditional medicine for the treatment of rheumatoid arthritis, diabetes, infertility and impotence. The present study evaluated the potential toxicity of aqueous extract of aerial parts of Caralluma dalzielii (AECD) through acute and sub-acute oral administration in mice and rats. During acute toxicity study, female mice and rats were orally administered with AECD at single doses of 175, 500 and 2000 mg/kg according to OECD Guidelines 425. Sub-acute toxicity of AECD (150, 300 and 600 mg/kg p.o) was studied by daily dosing of Wistar rats of both sexes for 28 days. The acute toxicity study revealed no lethal effects and behavioural signs of toxicity at the tested doses indicating that LD50 is greater than 2000 mg/kg. In sub-acute study, a significant reduction in the body weight (p < 0.05), feed and water (p < 0.001) intake of the rats were observed. A significant (p < 0.05) increase in lymphocytes, mean platelet volume counts and alanine aminotransferase were also observed. Histopathological analysis showed mild liver cell distortion in female rats treated at 600 mg/kg of AECD. These results show low toxicity of AECD on short-term use and liver toxicity on long-term use.