RESUMO
Aims: Evaluation of natural antioxidant potential of Kalanchoe pinnata leaves attributable towards its therapeutic properties. Study Design: In vitro experiments to validate antioxidant potential in aqueous and lipid phase. Methodology: The aqueous-alcoholic whole leaf extract designated as KPE (K. pinnata extract) was subjected to comprehensive biochemical analysis to reveal its natural strength as an antioxidative agent. In lipid protection ability assay where lipid phase (preemulsion) was prepared using linoleic acid with Fe2+, Fe3+ and Cu2+ as stress-inducers, it’s potential to protect against peroxyl radical induced damage in non aqueous environment was tested. Deoxy-D-ribose degradation assay in presence or absence of chelating agent (EDTA) was tested to reveal non site-specific and site-specific hydroxyl radical (OHº) scavenging potential respectively. Sodium nitroprusside based nitric oxide (NO) quenching activity and nitroblue tetrazolium reduction based superoxide radical scavenging potential were also estimated. Results: Total phenolic content of KPE was 28.4±2 μg mg-1. In lipid protection ability assay it exhibited maximally restricted Fe2+ induced amplification of peroxyl raical (ROOº)at 10 mg mL-1. It elicited a significant (P = .05) inhibition of lipid auto-oxidation by directly scavenging peroxyl radicals. In potassium ferrithiocyanate-based reducing power assay, KPE exhibited significantly higher potency as compared to the standard synthetic antioxidant butylated hydroxy toluene (BHT), in the range of 100-2000 μg mL-1. The ability of KPE to interact at the level of generation of hydroxyl radicals was also tested with deoxy-D-ribose degradation assay that revealed a two-fold higher non site-specific OHº scavenging potential than its site-specific activity. In sodium nitroprusside based NO quenching assay KPE showed >50% quenching activity at 0.5 mg mL-1. Conclusions: KPE is a rich source of anti-oxidative properties and has strong protective potential against oxidative stress in both aqueous and lipid phases. Hydroxyl radical scavenging assay showed KPE’s ability to scavenge free radicals is more due to its reductive potency than its metal-chelation activity attributable towards its exploration in herbal drug discovery research.
RESUMO
Influenza A (H1N1) virus, a genetic reassortment of endemic strain of human, avian flu and swine flu, with an inherent ability to mutate continuously has developed a subtype which is causing present flu in humans. As on 10th May, 2009, twenty nine countries are affected with officially reported 4379 cases with Mexico – 1626 affected (45 deaths), US 2254 affected (02 deaths); Canada 280 (01 deaths) and Costa Ricia -8 cases (01 death) respectively. Rest of 15 countries have reported less than 100 officially confirmed cases of H1N1 infection. WHO has already declared Pandemic Alert V on 29th April, 2009. If the present flu achieves equivalent virulence to that of 1918-19 pandemic flu, expected deaths will be 62 million people. Travel advisory, stockpiling of antiviral drugs – Tamiflu & Relenza; vaccine development, activation of business continuity planning for maintenance of essential serives etc., are some of the important mitigation approaches, being followed all over the world. WHO has a regional reserve of 10,000 million doses of anti-viral drugs. National Disaster Management Authority (NDMA), Government of India, an apex body for disaster management, in active coordination with Ministry of Health & other stakeholders/service providers is maintaining a constant state of vigil on the present Influenza A (H1N1) outbreak. In collaboration with UNDMT, NDMA has outlined a strategy for Pandemic Preparedness beyond Health in April, 2008. Various non-pharmaceutical interventions like detection, isolation and quarantine are required to contain the situation. Accordingly, stockpiling of 10 million doses of anti viral drugs, surveillance at airports, isolation with strict enforcement of quarantine procedures, sustained supply of respiratory masks & other personal protective equipment; deployment of rapid response teams are some of the activities being undertaken by Indian Government proactively. As situation goes to Phase VI, there will be a shift in strategy from active surveillance, detection and quarantine to containment, treatment, prevention of spread of disease and maintenance of business continuity beyond health sectors. The major concern is to utilise this latency period, between phase V and VI, to fill the gaps in state of preparedness. It is also essential to focus on development/procurement of appropriate vaccine to manage the situation arising from any further mutation of the existing causative virus to be resistant against existing anti viral therapies. It is a continued effort which can save many lives around the world and everyone has to play its assigned role effectively.