Sekh Abdul Nasim

Physiological and antioxidant responses of Salvinia natans exposed to chromium-rich wastewater

Salvinia natans possess capacity to accumulate high concentrations of chromium (Cr). Studies were carried out to evaluate physiological efficiency and defensive potential of plant exposed to Cr-rich wastewater. Among photochemical reactions, photosystem I (PS I) and photosystem II (PS II) activity noted an increase in plants exposed to Cr-rich wastewater. Fluorescence ratio F(v)/F(m) depicted no alteration in plants exposed to Cr. The activity of ribulose-1,5-biphosphate carboxylase-oxygenase (Rubisco) noted a decline, while transthylakoidal pH gradient (DeltapH) (correlative of photophosphorylation) showed increase in plants exposed to Cr-rich wastewater. Plants lacked the ability to produce malondialdehyde, but possessed efficient enzymic and non-enzymic antioxidant defense mechanisms that played important role in curtailing oxidative stress. The activities of antioxidant enzymes showed alleviation in plants exposed to Cr-rich wastewater. The levels of cellular antioxidants noted decline suggesting a defensive role in protection against oxidative stress caused by Cr. The present findings suggest that Salvinia possess efficient antioxidant machinery that curtails oxidative stress caused by Cr-rich wastewater and protects photosynthetic machinery from damage.

Heavy Metals Alter the Potency of Medicinal Plants

There has been increased use of herbal drugs in recent years. Because of increasing demand and wider use, it is essential that the quality of plant-based drugs should be assured prior to use. When heavy metals contaminate the plants from which herbal drugs are derived, they affect both plant growth characteristics and production of secondary plant metabolites. Plants exposed to heavy metal stress show changes in production of secondary metabolites. High levels of heavy metal contamination in medicinal or other plants may suppress secondary metabolite production. Alternatively, the presence of heavy metals in medicinal plants may stimulate production of bioactive compounds in many plant species. Moreover, some research results suggest that heavy metals may play an important role in triggering plant genes to alter the titers or nature of secondary plant metabolites, although the exact mechanism by which this happens remains unclear. Oxidative stress induced by heavy metals triggers signaling pathways that affect production of specific plant metabolites. In particular, reactive oxygen species (ROS), generated during heavy metal stress, may cause lipid peroxidation that stimulates formation of highly active signaling compounds capable of triggering production of bioactive compounds (secondary metabolites) that enhances the medicinal value of the plant. As usual, further research is needed to clarify the mechanism by which heavy metals induce responses that result in enhanced secondary metabolite production.

Alliin obtained from leaf extract of garlic grown under in situ conditions possess higher therapeutic potency as analyzed in alloxan-induced diabetic rats.

Context: Garlic, Allium sativum L. (Liliaceae), possesses high therapeutic and pharmacological properties. Hypoglycemic activity is attributed to alliin (S-allyl cysteine sulfoxide), the main active principle localized in garlic cloves. Objective: To compare the production and therapeutic efficiency of alliin extracted from garlic leaves of plants grown under ex situ and in situ conditions. Materials and methods: Alliin content of leaves was quantified and aqueous leaf extracts (from ex situ and in situ grown plants) were given to normal and alloxan-induced diabetic rats for five weeks. Results: Alliin production noted ~50% enhancement in leaves from plants grown under in situ conditions. Serum glucose, triglycerides, total lipids, total cholesterol, low-density lipoprotein (LDL)-, and very low-density lipoprotein (VLDL)-cholesterol in diabetic rats treated with alliin produced from in situ grown plants noted significant reduction of ~54%, 15%, 14%, 20%, 24%, and 15%, while 35%, 14%, 10%, 12%, 17% and 11% reduction was noted in diabetic rats treated with alliin produced from ex situ grown plants in comparison with those administered with distilled water. High-density lipoprotein (HDL)-cholesterol did not show any significant change. Leaf extract of plants lowered serum enzyme levels (alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase) toward the norm better than glibenclamide. The histopathological alteration in pancreas caused by alloxan was also reduced by leaf extract. Discussion and conclusion: These findings demonstrate leaf extract obtained from plants grown under in situ condition possess higher therapeutic efficiency in comparison with leaf extract obtained from plants grown under ex situ condition. Studies suggest that environmental factors influence production of alliin and its therapeutic potential.

Heavy Metal Removal Potential of Dried Salvinia Biomass

Investigations were carried out to evaluate heavy metal adsorption capacity of Salvinia. Batch experiments showed that dry plant biomass possess good potential to adsorb heavy metals such as Ni, Co, Cr, Fe, and Cd. The metal adsorption increased with increase in initial metal concentration. The data obtained fitted well with Freundlich equilibrium isotherm. Further characterization of plant biomass showed presence of both acidic and basic surface functionalities that might facilitate binding of metal ions. Fourier transform infrared (FTIR) spectra of plant biomass suggested involvement of carbonyl (C˭O), carboxyl (-COO), and hydroxyl (-OH) groups in binding heavy metals to plant biomass. The studies establish S. natans as an effective biosorbent for removing heavy metals from wastewater and further emphasize biomass utilization in wastewater treatment technologies.

Nanocurcumin: a novel antifilarial agent with DNA topoisomerase II inhibitory activity

Abstract Objective: The aim of this study is to evaluate the antifilarial, antiwolbachial and DNA topoisomerase II inhibitory activity of nanocurcumin (nano-CUR). Methods: Nano-CUR formulations (F1–F6) were prepared using free radical polymerization and were characterized by particle size, morphology, encapsulation efficiency and in vitro release kinetics. Antifilarial potential was evaluated in vivo against Brugian filariasis in an experimental rodent model, Mastomys coucha, by selecting the formulation that maximized parasite elimination characteristics. Wolbachial status was determined by PCR and a relaxation assay was used to estimate DNA topoisomerase II inhibitory activity. Results: Nano-CUR (F3) having a 60 nm diameter and 89.78% entrapment efficiency showed the most favorable characteristics for the elimination of filarial parasites. In vivo pharmacokinetic and organ distribution studies demonstrate significantly greater C(max) (86.6 ± 2.56 ng ml−1), AUC0–∞ (796 ± 89.8 ng d ml−1), MRT (19.5 ± 7.82 days) and bioavailability of CUR (70.02%) in the organs from which the adult parasites were recovered. The optimized nano-CUR (F3) (5 × 5 mg/kg, orally) significantly augmented the microfilariciadal and adulticidal action of CUR over free CUR (5 × 50 mg/kg, orally) or Diethylcarbamizine (50 mg/kg, orally) against the Brugia malayi Mastomys coucha rodent model. The PCR results showed complete elimination of wolbachia from the recovered female parasites. Interestingly, nano-CUR was also found to be a novel inhibitor of filarial worm DNA topoisomerase II, Setaria Cervi in vitro. Conclusion: This study recognizes the beforehand antimicrofilarial, antimacrofilarial, anti-wolbachial activity of nano-CUR (F3) over free forms and additionally its strong inhibitory action against the major target filarial parasite enzyme DNA topoisomerase II in vitro.