1H nuclear magnetic resonance-based metabolite profiling of guava leaf extract: an attempt to develop a prototype for standardization of plant extracts.

BACKGROUND: Herbal medicines are fast gaining popularity. However, their acceptability by modern practitioners is low which is often due to lack of standardization. Several approaches towards standardization of herbals have been employed. The current study attempted to recognize key peaks from 1H NMR spectra which together would comprise of a spectral fingerprint relating to efficacy of Psidium guajava (guava) leaf extract as an antidiarrhoeal when a number of unidentified active principles are involved. METHODS: Ninety samples of guava leaves were collected from three locations over three seasons. Hydroalcoholic (water and ethanol, 50:50) extracts of these samples were prepared and their 1H NMR spectra were acquired. Spectra were also obtained for quercetin, ferulic acid and gallic acid as standards. Eight bioassays reflecting different stages of diarrhoeal pathogenesis were undertaken and based on pre-decided cut-offs, the extracts were classified as 'good' or 'poor' extracts. The bioactivity data was then correlated with the 1H NMR profiles using Regression or Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA). RESULTS: OPLS-DA showed seasonal and regional segregation of extracts. Significant models were established for seven bioassays, namely those for anti-bacterial activity against Shigella flexneri and Vibrio cholerae, adherence of E. coli, invasion of E. coli and S. flexneri and production and binding of toxin produced by V. cholerae. It was observed that none of the extracts were good or bad across all the bioassays. The spectral analysis showed multiple peaks correlating with a particular activity. Based on NMR and LC-MS/MS, it was noted that the extracts contained quercetin, ferulic acid and gallic acid. However, they did not correlate with the peaks that segregated extracts with good and poor activity. CONCLUSIONS: The current study identified key peaks in 1H NMR spectra contributing to the anti-diarrhoeal activity of guava leaf extracts. The approach of using spectral fingerprinting employed in the present study can thus be used as a prototype towards standardization of plant extracts with respect to efficacy.

Psidium guajava: A Single Plant for Multiple Health Problems of Rural Indian Population.

The rural population in India faces a number of health problems and often has to rely on local remedies. Psidium guajava Linn. (guava), a tropical plant which is used as food and medicine can be used by rural communities due to its several medicinal properties. A literature search was undertaken to gauge the rural health scenario in India and compile the available literature on guava so as to reflect its usage in the treatment of multiple health conditions prevalent in rural communities. Towards this, electronic databases such as Pubmed, Science Direct, google scholar were scanned. Information on clinical trials on guava was obtained from Cochrane Central Register of Controlled Trials and Clinicaltrial.gov. The literature survey revealed that guava possesses various medicinal properties which have been reported from across the globe in the form of ethnobotanical/ethnopharmacological surveys, laboratory investigations and clinical trials. Besides documenting the safety of guava, the available literature shows that guava is efficacious against the following conditions which rural communities would encounter. (a) Gastrointestinal infections; (b) Malaria; (c)Respiratory infections; (d) Oral/dental infections; (e) Skin infections; (f) Diabetes; (g) Cardiovascular/hypertension; (h) Cancer; (i) Malnutrition; (j) Women problems; (k) Pain; (l) Fever; (m) Liver problems; (n) Kidney problems. In addition, guava can also be useful for treatment of animals and explored for its commercial applications. In conclusion, popularization of guava, can have multiple applications for rural communities.

Fate of ß-asarone in Ayurvedic Sodhana process of Vacha.

BACKGROUND: Calamus (Acorus calamus Linn., Araceae) rhizome synonymously called sweet flag or Vacha is an aromatic herb indigenous to Central Asia and Eastern Europe. It has been used by the Ayurvedic practitioners since time immemorial for diseases ranging from weakness of memory to being used as an anthelminthic. Reports of its use have been found in books like Charak Samhita, Sushruta Samhita, etc., The major constituent of the oil of Vacha is a phenyl propanoid called ß-asarone, which is reported to show carcinogenic properties. Due to the toxic effects of ß-asarone, sodhana prakriya (detoxification process) has been prescribed for Vacha before its inclusion in the Ayurvedic medicines. Shodhanaprakriya (S. prakriya) of Vacha has been mentioned in the Ayurvedic texts. OBJECTIVES: This study was undertaken with an aim to find out the mechanism involved in the S. prakriya of Vacha and also to suggest an alternate method for the conventional one. MATERIALS AND METHODS: The conventional method was studied in the laboratory and equivalent alternate methods were designed based on the mechanism involved. Vacha samples were subjected to the conventional method as well as the alternate methods and the content of ß-asarone in the different samples was monitored using Gas Chromatography technique. RESULTS: Various alternate methods have been devised based on the mechanism involved in the S. prakriya which have given results comparable with those of the conventional method. CONCLUSION: The scientific mechanism involved in the S. prakriya of Vacha has been established and alternate methods have been proposed.