Rebamang A. Mosa

In Vivo Antihyperglycemic Activity of a Lanosteryl Triterpene from Protorhus longifolia

Control of postprandial hyperglycemia is crucial in the management of diabetes mellitus. Despite the use of the current hypoglycemic drugs, incidence of diabetes and related diseases continue to increase. This study aimed at evaluating the in vivo antihyperglycemic activity of methyl-3β-hydroxylanosta-9,24-dien-21-oate (RA-3), a lanosteryl triterpene isolated, and characterized from Protorhus longifolia stem bark. Spectroscopic data analysis was used to establish and verify the structure of the triterpene. The antihyperglycemic activity of the triterpene was evaluated in an STZ-induced diabetes rat model. The experimental animals were orally administered with RA-3 (100 mg/kg body weight) daily for 14 days. An oral glucose tolerance test was also performed. The animals were euthanized and biochemical analysis of antioxidant status, some glycolytic enzymes and glycogen content were conducted on serum and liver samples, respectively. RA-3 exhibited hypoglycemic activity by reducing blood glucose levels by 37%. The triterpene also improved glucose tolerance in the diabetic rats. Relatively higher hepatic glycogen content, hexokinase and glucokinase activity with a decrease in glucose-6-phosphatase activity were observed in the triterpene-treated diabetic group when compared with the diabetic control group. The triterpene treatment further increased antioxidant status of the diabetic animals; increased activity of superoxide dismutase and catalase were observed along with a decrease in malondialdehyde content. The results indicate potential pharmaceutical effects of lanosteryl triterpene in the management of diabetes mellitus.

In vitro antihyperlipidemic potential of triterpenes from stem bark of Protorhus longifolia.

Two lanostane triterpenes, 3β-hydroxylanosta-9,24-dien-21-oic acid (1) and methyl-3β-hydroxylanosta-9,24-dien-21-oate (2), were isolated from the stem bark of Protorhus longifolia. Their structures were deduced on the basis of spectroscopic analysis (NMR, HRMS, IR). This study investigated the in vitro anti-adipogenic activity of the two triterpenes. Their inhibitory activity was evaluated on selected lipid digestive enzymes (pancreatic lipase and cholesterol esterase). The inhibitory activity of the compounds on hormone-sensitive lipase and their ability to bind bile acids were also evaluated. The effect of the compounds on glucose uptake in C2C12 muscle cells and 3T3-L1 adipocytes, and on triglyceride accumulation in 3T3-L1 adipocytes was investigated. The triterpenes effectively inhibited the activities of the enzymes with IC50 values ranging from 0.04 to 0.31 mg/mL. The compounds showed a high affinity for secondary bile acids. Both compounds stimulated glucose uptake in C2C12 muscle cells and 3T3-L1 adipocytes. Compound 1 significantly reduced triglyceride accumulation in mature differentiated 3T3-L1 adipocytes. It is apparent that these lanostane triterpenes enhance glucose uptake and suppress adipogenesis, which together with their inhibitory effects on lipid digestive enzymes suggests that they have antihyperlipidemic potential.

Antibacterial activity of two triterpenes from stem bark of Protorhus longifolia

Antibiotic resistance of pathogenic strains has hugely contributed to the wide spread of new and re-emerging infectious diseases. There is thus the need for the discovery of new (non-penicillin based) antibiotics. The triterpenes [3β-hydroxylanosta-9,24-dien-21-oic acid (1) and methyl-3β-hydroxylanosta-9,24-dienoate (2)] isolated from stem bark of Protorhus longifolia (Benrh.) Engl. were evaluated for their antibacterial activity against a panel of selected general and antibiotic resistant Gram positive and Gram negative bacteria. The antibacterial activity of the compounds was determined using disc diffusion method. The compounds exhibited antibacterial activity against most of the tested bacteria with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranging from 0.16 to 5.00 mg/ml and 0.63 to 5.00 mg/ml, respectively. The triterpenes did not exhibit any bacterial DNA damaging effects, but apparently affected the microbial cell membrane integrity. The triterpenes could be a potentially effective antimicrobial agent to combat infectious diseases. Key words: Triterpenes, antibacterial activity, antibiotic resistance, DNA damage.

A Lanosteryl Triterpene from Protorhus longifolia Improves Glucose Tolerance and Pancreatic Beta Cell Ultrastructure in Type 2 Diabetic Rats

Type 2 diabetes remains one of the leading causes of death worldwide. Persistent hyperglycemia within a diabetic state is implicated in the generation of oxidative stress and aggravated inflammation that is responsible for accelerated modification of pancreatic beta cell structure. Here we investigated whether a lanosteryl triterpene, methyl-3β-hydroxylanosta-9,24-dien-21-oate (RA-3), isolated from Protorhus longifolia can improve glucose tolerance and pancreatic beta cell ultrastructure by reducing oxidative stress and inflammation in high fat diet and streptozotocin-induced type 2 diabetes in rats. In addition to impaired glucose tolerance, the untreated diabetic rats showed increased fasting plasma glucose and C-peptide levels. These untreated diabetic rats further demonstrated raised cholesterol, interleukin-6 (IL-6), and lipid peroxidation levels as well as a destroyed beta cell ultrastructure. Treatment with RA-3 was as effective as metformin in improving glucose tolerance and antioxidant effect in the diabetic rats. Interestingly, RA-3 displayed a slightly more enhanced effect than metformin in reducing elevated IL-6 levels and in improving beta cell ultrastructure. Although the involved molecular mechanisms remain to be established, RA-3 demonstrates a strong potential to improve pancreatic beta cell ultrastructure by attenuating impaired glucose tolerance, reducing oxidative stress and inflammation.

Cardioprotective potential of a lanosteryl triterpene from Protorhus longifolia.

Abstract Context: The current rapid increase in the incidence of cardiovascular events indicates a need for the discovery of more effective cardioprotective agents. Objective: This study evaluated the cardioprotective potential of a lanosteryl triterpene from Protorhus longifolia (Benrh.) Engl. stem bark. Materials and methods: Spectroscopic data analysis was used to confirm the structure of methyl-3β-hydroxylanosta-9, 24-dien-21-oate (RA-3). The cardioprotective effect of RA-3 in isoproterenol-induced myocardial injury in hyperlipidemic rats was investigated. Rats were divided into the normal diet (ND) fed and high fat diet (HFD) fed groups. The HFD rats were further subdivided into three groups. The experimental group was orally administered with RA-3 (100 mg/kg) for 15 days. The rats were then injected with isoproterenol (85 mg/kg) to induce myocardial injury. At the end of the experiment, hearts and blood tissues were collected and used for histology and biochemical assays, respectively. Results: RA-3 exhibited a cardioprotective effect as it minimized myocardial injury in HFD rats. Few lesions of acute hyaline degeneration and reduced fat deposition were observed in the heart tissue of the triterpene pretreated rats. Lactate dehydrogenase (LDH) activity was decreased in the blood of the RA-3 pretreated rats (44.1 mU/mL) compared to the untreated group (64.8 mU/mL). Increased glutathione (GSH) content and catalase (CAT) activity along with lower levels of malondialdehyde (MDA) in the triterpene pretreated animals (120.8 nmol/μL) than in the non-treated HFD fed rats (143.6 nmol/μL) were also observed. Discussion and conclusion: The cardioprotective effect exhibited by RA-3 indicates its potential use in the management of cardiovascular diseases (CVD) and related health problems.

Comparative analyses and structural insights of the novel cytochrome P450 fusion protein family CYP5619 in Oomycetes

Phylogenetic and structural analysis of P450 proteins fused to peroxidase/dioxygenase has not been reported yet. We present phylogenetic and in silico structural analysis of the novel P450 fusion family CYP5619 from the deadliest fish pathogenic oomycete, Saprolegnia diclina. Data-mining and annotation of CYP5619 members revealed their unique presence in oomycetes. CYP5619 members have the highest number of conserved amino acids among eukaryotic P450s. The highest number of conserved amino acids (78%) occurred in the peroxidase/dioxygenase domain compared to the P450 domain (22%). In silico structural analysis using a high-quality CYP5619A1 model revealed that CYP5619A1 has characteristic P450 structural motifs including EXXR and CXG. However, the heme-binding domain (CXG) in CYP5619 members was found to be highly degenerated. The in silico substrate binding pattern revealed that CYP5619A1 have a high affinity to medium chain fatty acids. Interestingly, the controlling agent of S. diclina malachite green was predicted to have the highest binding affinity, along with linoleic acid. However, unlike fatty acids, none of the active site amino acids formed hydrogen bonds with malachite green. The study’s results will pave the way for assessing CYP5619A1’s role in S. diclina physiology, including the nature of malachite green binding.

Testicular Dysfunction Ameliorative Effect of the Methanolic Roots Extracts of Maytenus procumbens and Ozoroa paniculosa

The traditional use of medicinal plants in the management of sexual dysfunctions has a long history. This study investigated testicular dysfunction ameliorative effect of the methanolic roots extracts of Maytenus procumbens and Ozoroa paniculosa in a butanol-induced testicular dysfunction rat model. The rats in respective experimental groups were orally administered with the extract at 50 and 250 mg/kg bw, daily for 28 days. The cytotoxicity of the extracts was evaluated against HEK293, MCF-7, and HT29 cell lines. The extracts exhibited moderate (LC50 30.3–330.2 μg/mL) to weak (LC50 200.8–438.4 μg/mL) cytotoxicity level on the cancer and normal cells, respectively. While relatively lower serum testosterone levels and total sperm count along with decreased numbers of spermatogonia were noted in the untreated group, all these parameters were improved in the groups treated with the extracts at 250 mg/kg. Improved histomorphological changes of the testes were also observed when compared to the untreated group. While the extracts (at 250 mg/kg) increased serum reduced glutathione content and decreased malondialdehyde content, a relatively higher serum creatinine level was also observed in the treated animals group. The results indicate that the two plant extracts have potential to ameliorate testicular dysfunction.