Acute and sub chronic toxicity studies with herbal pain relieving formula (Rhuleave-K™) in rats.

Rhuleave-K™ is a proprietary combination of Curcuma longa extract, Boswellia serrata extract and black sesame seed oil. Acute toxicity was evaluated as per OECD guidelines 423. Rhuleave-K™ was fed at 2000 mg/kg to overnight fasted female rats. Clinical signs of abnormality and mortality was observed daily for 14 days. Sub-chronic toxicity was studied by feeding Rhuleave-K™ at 100, 500 and 1000 mg/kg/day to rats as per OECD guidelines 408. After 90 days feeding, hematological and biochemical parameters were analyzed. Histopathology of all the major organs was also studied. In the acute toxicity study, there was no clinical sign of toxicity in any of the rats at maximum dose of 2000 mg/kg. The LD50 was computed as >2000 mg/kg in rats. The repeated dosing of Rhuleave-K™ at the maximum dose level of 1000 mg/kg for 90 days did not induce any observable toxic effects in rats, when compared to its corresponding control. The hematology and biochemistry profiles of treated rats were similar to control animals and difference was non-significant (p > 0.05). The histopathology of major organs of all the control and treated animals was normal. In this study the NOAEL for Rhuleave-K™ was calculated as 1000 mg/kg daily in rats.

Curcumin and metformin-mediated chemoprevention of oral cancer is associated with inhibition of cancer stem cells.

Effective chemoprevention is critical for improving outcomes of oral cancer. As single agents, curcumin and metformin are reported to exhibit chemopreventive properties, in vitro as well as in patients with oral cancer. In this study, the chemopreventive efficacy of this drug combination was tested in a 4-nitro quinoline-1-oxide (4NQO) induced mice oral carcinogenesis model. Molecular analysis revealed a cancer stem cell (CSC)-driven oral carcinogenic progression in this model, wherein a progressive increase in the expression of CSC-specific markers (CD44 and CD133) was observed from 8th to 25th week, at transcript (40-100-fold) and protein levels (P ≤ 0.0001). Chemopreventive treatment of the animals at 17th week with curcumin and metformin indicated that the combination regimen decreased tumor volume when compared to the control arm (0.69+0.03 vs 6.66+2.4 mm3 ; P = 0.04) and improved overall survival of the animals (P = 0.03). Assessment of the molecular status showed an overall downregulation of CSC markers in the treatment arms as compared to the untreated control. Further, in vitro assessment of the treatment on the primary cells generated from progressive stages of 4NQO-induced mice tissue showed a concordant and consistent downregulation of the CSC markers following combination treatment (P < 0.05). The treatment also inhibited the migratory and self-renewal properties of these cells; the effect of which was prominent in the cultures of early dysplastic tissue (P < 0.002). Collectively, our observations suggest that the combination of curcumin and metformin may improve chemopreventive efficacy against oral squamous cell carcinoma through a CSC-associated mechanism.

Systematic and comprehensive investigation of the toxicity of curcuminoid­essential oil complex: A bioavailable turmeric formulation.

Curcumin, the active component present in Curcuma longa of the family Zingiberaceae, has a number of pharmacological effects, including potential anti­inflammatory activity. One of the major limitations of curcumin/turmeric extract is its poor absorption through the gastrointestinal tract. Several approaches have been adopted to increase the bioavailability of curcumin, including loading curcumin into liposomes or nanoparticles, complexation with phospholipids, addition of essential oils and synthesizing structural analogues of curcumin. In the present study, the toxicity and safety of one such bioavailable turmeric formulation, curcuminoid­essential oil complex (CEC), the toxicity profile of which has not been reported, were examined using in vivo and in vitro models, as per the guidelines of the Organisation for Economic Co-operation and Development. Investigations of acute toxicity study were performed in rats and mice, and the results revealed no signs and symptoms or toxicity or mortality in any of the animals at the maximum recommended dose level of 5,000 mg/kg body weight. The repeated administration of CEC for 90 days in Wistar rats at a dose of 1,000 mg/kg body weight did not induce any observable toxic effects, compared with corresponding control animals. Mutagenicity/genotoxicity investigations were also performed using a bacterial reverse mutation assay (Ames test), a mammalian bone marrow chromosome aberration test and a mammalian erythrocyte micronucleus test in mice. CEC was found to be non­mutagenic in all three mutagenic investigations. Consequently, the present study indicated that CEC elicited no toxic effects in animals or in vitro. Therefore, following investigations of acute toxicity, repeated dose toxicity and mutagenicity, CEC was deemed a safe, non­toxic pharmacological formulation.

A-90 Day Gavage Safety Assessment of Boswellia serrata in Rats.

The present study deals with the evaluation and assessment of the safety/toxic potential of Boswellia serrata, a well known Ayurvedic herb used to treat disorders of digestive system, respiratory ailments and bone related diseases. A repeated dose oral (90 days) toxicity study of Boswellia serrata was carried out. For this, 10 rats of each sex were treated with the Boswellia serrata at three different doses i.e. 100, 500 and 1000 mg/kg B. wt. /day. As a control, 10 rats of each sex were treated with corn oil only which was the vehicle. Two groups consisting of five male and five female rats were kept as control recovery and high dose recovery group which were treated with the vehicle (corn oil) and the Boswellia serrata at the dose of 1000 mg/kg B. wt. Animals of control recovery and high dose recovery groups were further observed for 28 days without any treatment. From this study, it was found that the rats treated with high dose of the Boswellia serrata gained their body weight with much less rate than that of the control group. However, during the recovery period, the loss in body weight gain as observed during the study period exhibits a reversible effect on the metabolic activity and recovered. The results also indicate that Boswellia serrata is relatively safe in rat up to the dose of 500 mg/kg B.wt. as no adverse impact on health factors was observed. Thus, the No observed adverse effect level is 500 mg/kg B. wt.