Review of Phytochemicals and Plant Extracts With Activity against Viruses and Protozoal Keratitis: In Vitro and In Vivo.

Abstract: Now a days Infectious keratitis is a leading cause of vision loss and total blindness world- wide. Proper diagnosis of causative organism is critical and although culture remains the prevailing diagnostic tool, newer techniques such as in vivo and in vitro plant extract are helpful for diagnosing Viral and Acanthamoeba. Next generation sequencing holds the potential for early and accurate diagnosis even for organisms that are difficult to culture by conventional method. In this review we covered types & various etiological agent that basically protozoa, viruses. The epidemiology & risk factor like contact lenses use, eye trauma, surface eye diseases, immunosuppression, agricultural work, and also emphasizing on the current treatment strategies and their limitations by using antiviral and antiprotozoal phytochemicals, also consist of need for novel therapeutic agents. We also covered types of phytochemicals and their classes like flavonoid, polyphenols, terpenoids etc. along with their sources, and extraction, and their families. Rationale for using phytochemicals in prevention of viral and acanthamoeba keratitis as antiviral and antiprotozoal agents include anti- inflammatory, antimicrobial, antioxidant, and immunomodulatory properties, also phytochemicals are plant derived products, so they have natural body acceptance. We also focused on mechanism of action and structural activity relationship of phytochemicals, their safety, efficacy and cytotoxicity to corneal cell. We also focused on how nanotechnology is useful for increment in efficacy and bioavailability at ocular surface. Methodologies such as MTT, PCR are also useful for this purpose. The combination therapies and also identification of gaps in current research and need for well designed in vitro and in vivo ,importance of standardized extracts and purified compounds ,development of suitable formulations for ocular delivery plays key role in keratitis prevention. (Key words: keratitis, antiviral, antiprotozoal, phytochemical)