Helicobacter pylori (H. pylori) is a gram negative microaerophilic bacterium which resides in the mucous linings of the stomach. It has been implicated in the causation of various gastric disorders including gastric cancer. The geographical distribution and etiology of gastric cancer differ widely in different geographical regions and H. pylori, despite being labeled as a grade I carcinogen, has not been found to be associated with gastric cancer in many areas. Studies in Asian countries such as Thailand, India, Bangladesh, Pakistan, Iran, Saudi Arabian countries, Israel and Malaysia, have reported a high frequency of H. pylori infection co-existing with a low incidence of gastric cancer. In India, a difference in the prevalence of H. pylori infection and gastric cancer has been noted even in different regions of the country leading to a puzzle when attempting to find the causes of these variations. This puzzle of H. pylori distribution and gastric cancer epidemiology is known as the Indian enigma. In this review we have attempted to explain the Indian enigma using evidence from various Indian studies and from around the globe. This review covers aspects of epidemiology, the various biological strains present in different parts of the country and within individuals, the status of different H. pylori-related diseases and the molecular pathogenesis of the bacterium.
The quest for safe chemotherapy has attracted researchers to explore anticancer potential of herbal medicines. Owing to upsurging evidence of herbal drug's beneficial effects, hopes are restored for augmenting survival rates in cancer patients. However, phytoconstituents confronted severe limitations in terms of poor absorption, low-stability, and low bioavailability. Along with toxicity issues associated with phytoconstituents, quality control and limited regulatory guidance also hinder the prevalence of herbal medicines for cancer therapy. Attempts are underway to exploit nanocarriers to circumvent the limitations of existing and new herbal drugs, where biological macromolecules (e.g., chitosan, hyaluronic acid, etc.) are established highly effective in fabricating nanocarriers and cancer targeting. Among the discussed nanocarriers, liposomes and micelles possess properties to cargo hydro- and lipophilic herbal constituents with surface modification for targeted delivery. Majorly, PEG, transferrin and folate are utilized for surface modification to improve bioavailability, circulation time and targetability. The dendrimer and carbon nanotubes responded in high-loading efficiency of phytoconstituent; whereas, SLN and nanoemulsions are suited carriers for lipophilic extracts. This review emphasized unveiling the latent potential of herbal drugs along with discussing on extended benefits of nanocarriers-based delivery of phytoconstituents for safe cancer therapy owing to enhanced clinical and preclinical outcomes without compromising safety.