Evaluation of Safety, Antioxidant Effects and Antiurolithiatic Potentials of Selected Ethiopian Medicinal Plant Extracts
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Date
2021-06-19
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Addis Ababa University
Abstract
Urolithiasis is a public health problem with limited treatment options. In the Ethiopian folk medicine, there is a claim that medicinal plants can treat urolithiasis. The present study investigated the safety, antioxidant activities and antiurolithiatic efficacies of Achyrathes aspera, Rumex abyssinicus, Satureja punctata, Chenopodium murale, Aloe pulcherrima, Chenopodium ambrosioides, Inula confertiflora, Gomphocarpus fruticosus and Commiphora myrrha extracts. Primarily, thirteen years retrospective clinical records from St. Paul's Tertiary Referral Hospital were retrieved and analyzed to estimate the overall prevalence of urolithiasis in Ethiopia. In addition, plant extracts were tested for acute and sub-acute toxicity in female Wistar rats. The in vitro DPPH (2,2-diphenyl-1-picrylhydrazyl) and calcium oxalate (CaOx) assays were measured using UV-Vis-NIR spectrophotometery. Also, urolithiasis was induced in male Wistar rats by feeding ethylene glycolated (0.75%) water for 28 days. Preventive and curative studies were based on oral exposure of rats to 200 mg/kg extracts for 14 and 28 days, respectively. Urine samples were collected on 13th and 27th day before sacrificing the rats, whereas the liver and kidneys collected after sacrificing on days 14 and 28. Blood samples were collected from retro-orbital sinus under the anaesthetic condition. The bioactive constituents of G. fruticosus extracts were characterized by GC-MS analysis. Among 32,370 surgically treated patients, referred from all over the country, 2.3% (757) urolithiatic cases were recorded. Trend analysis revealed an increasing prevalence of urinary stones. Acute toxicity tests resulted in body weight loss for C. murale, R. abyssinicus, C. ambrosioides and I. confertiflora extracts at dose 2000 mg/kg. Moreover, C. murale (p<0.001) extracts showed significant reduction in platelet count. iv
Histopathological studies for R. abyssinicus extract indicated mild liver injuries in sub-acute toxicity test. The DPPH scavenging capacities of S. punctata, G. fruticosus, and A. pulcherrima aqueous extracts were 92.3%, 81.6%, and 72.3%, respectively compared to ascorbic acid, the standard therapy in use, which showed 87.6%, 94.5%, and 92.3% at concentrations of 0.20 mg/ml, 0.78 mg/ml and 3.13 mg/ml, respectively. The IC50 antioxidant value of S. punctata aqueous extract was 0.01 ±0.003 mg/ml, compared to ascorbic acid (0.03 ±0.007 mg/ml). The in vitro inhibition of CaOx nucleation at 3200 g/ml aqueous extracts of A. pulcherrima (22.5%), S. punctata (26%) and G. fruticosus (37.6%) was observed in 30 minutes incubation; whereas their potency of aggregation inhibition at 200 g/ml was 32.9%, 3.8% and 33.3%, respectively. Likewise, the nucleation inhibition of G. fruticosus EtOAc fraction was 56.9%, and its fraction II aggregation inhibition was 58.9% at 3200 g/ml. Furthermore, in vivo studies also confirmed that S. punctata aqueous extract had CaOx deposition inhibitory effects in the preventive study (p<0.001), whereas G. fruticosus aqueous and EtOAc fraction (p<0.01) reduced CaOx deposition in curative study. In the urine, serum and kidney homogenates, stone forming constituents were lowered by G. fruticosus EtOAc fraction (p<0.05). GC-MS analysis of G. fruticosus fraction II revealed 29 compounds, of which di-isooctyl phthalate, n-hexadecanoic acid, isoborneol acrylate, and benzoic acid were the major constituents. In general, the in vitro and in vivo findings were found to be nearly complementary in demonstrating CaOx preventive and therapeutic potencies of S. punctata and G. fruticosus extracts, respectively. However, further investigation may be required to assess the efficacy of G. fruticosus major compounds and S. punctata fractions against urolithiasis.
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Keywords
Antioxidants, Gc-Ms Analysis, In Vitro, In Vivo, Medicinal Plants, Toxicity, Urolithiasis