Capitate glandular trichomes of Paragutzlaffia henryi harbor new phytotoxic labdane diterpenoids.

The morphology and chemical profile of the capitate glandular trichomes (CGTs) of Paragutzlaffia henryi (Acanthaceae) were investigated. Four new labdane diterpenoids named paraguhenryisins A-D (1-4), together with the known physacoztomatin (5), were localized to the CGTs using laser microdissection coupled with cryogenic (1)H NMR and HPLC analyses and were traced and isolated from the CGT extract of inflorescences. Their structures were determined by spectroscopic methods and single-crystal X-ray diffraction. Bioassays indicated significant inhibitory effect for these diterpenoids on Arabidopsis thaliana seed germination and seedling root elongation. The most potent inhibitor, paraguhenryisin C (3), was interestingly detected in both the rhizosphere soil and water rinsed inflorescences extract of P. henryi but not the roots, with average contents in the rhizosphere soil relevant to its phytotoxic EC50 values. These results suggested that phytotoxic labdane diterpenoids in the CGTs might be released into the environment as a defensive measure for P. henryi against other competitive plants.

H. Spinosa T. Anders ameliorates diabetic neuropathy in Wistar albino rats.

Diabetic neuropathic pain, an important microvascular complication in diabetes, is recognised as one of the most difficult types of pain to treat. The development of tolerance, inadequate relief, and potential toxicity of classical antinociceptives warrant the investigation of the newer agents to relieve this pain. Reactive oxygen/nitrogen species, increased oxidative stress, cytokines, and apoptosis are implicated in the pathogenesis of diabetic neuropathy. The aim of the present study was to explore the effect of methanolic extract of aerial parts of H. spinosa (HSME) on alloxan induced diabetic neuropathy in Wistar rats. Diabetic rats developed neuropathy after the third week of diabetes induction. Chronic treatment with HSME (250, 500, and 750 mg/kg body weight; p.o.) for 6 weeks starting from the 3rd week of alloxan injection showed significant increase in the pain threshold levels as compared to diabetic rats. HSME treated diabetic animals showed significant decrease in blood glucose level and increase in body weight as compared to diabetic control animals. The changes in lipid peroxidation status and antioxidant enzymes levels observed in sciatic nerve of diabetic rats were significantly restored by HSME treatment. Thus, the results suggest therapeutic potential of H. spinosa in treatment of diabetic neuropathy.

Subacute oral toxicity study of ethanolic leaves extracts of Strobilanthes crispus in rats.

OBJECTIVE: To examine the oral toxicity of repeated dosing of Strobilanthes crispus (S. crispus) ethanol leaves extract on the liver and kidney functions in Sprague Dawley rats. METHODS: Young female rats aged between 8 and 12 week-old were randomly assigned into four groups with five animals each group (n=5). The first group served as control, while the second, third and fourth groups were orally treated with a single dose daily with 150 mg/kg, 300 mg/kg, and 600 mg/kg of S. crispus ethanol leaves extract for 14 d consecutively. Cage-side observation was conducted for first 4 h after each dosing. The body weight changes, food consumptions and water intake were also recorded. Serum biochemical parameters, i.e., aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine and urea were determined at Day 15. All results were expressed as mean±SD and analysed using Dunnett's test. RESULTS: It was obtained that 14-day oral administration of S. crispus ethanol leaves extract did not cause any adverse effects or lethality to the female Sprague Dawley rats. No significant changes in serum biochemical parameters, relative organs weights, body weights, food intake and water consumptions were observed between the treatment groups and control. CONCLUSIONS: In conclusion, 14-day oral administration of S. crispus ethanol leaves extract was safe to be consumed in female rats without affecting the liver and kidney functions.

Acute toxicity and diuretic studies of Rungia repens aerial parts in rats.

Ethanolic extract of Rungia repens aerials parts (300 and 600 mg/kg p.o) showed diuretic activity in rats. The acute toxicity, orally evaluated in mice, was found to be higher than 3000 mg/kg.