A REVIEW ON THE MEDICINAL PLANT PSIDIUM GUAJAVA LINN. (MYRTACEAE)

Psidium guajava is an important food crop and medicinal plant available in tropical and subtropical countries, widely used in food and folk medicines around the world. It contains important phytoconstituents such as tannins, triterpenes, flavonoid: quercetin, pentacyclic triterpenoid: guajanoic acid, saponins, carotenoids, lectins, leucocyanidin, ellagic acid, amritoside, beta-sitosterol, uvaol, oleanolic acid and ursolic acid. In view of the immense medicinal importance of the plant, this review is an effort to compile all the information reported on its ethanobotanical, phytochemical and pharmacological activities. The present work attempts to generate interest among the masses regarding its potential in preventing and treating several common diseases. Many pharmacological studies have demonstrated the ability of this plant to exhibit antioxidant, hepatoprotective, anti-allergy, antimicrobial, antigenotoxic, antiplasmodial, cytotoxic, antispasmodic, cardioactive, anticough, antidiabetic, antiinflamatory and antinociceptive activities, supporting its traditional uses. Suggesting a wide range of clinical applications for the treatment of infantile rotaviral enteritis, diarrhoea and diabetes. Key words: ethanobotany, myrtaceae, pharmacology, physicochemical, phytochemical, Psidium guajav

Towards a critical understanding of the photosystem II repair mechanism and its regulation during stress conditions

Photosystem II (PSII) is vulnerable to high light (HL) illumination resulting in photoinhibition. In addition to photoprotection mechanisms, plants have developed an efficient PSII repair mechanism to save themselves from irreversible damage to PSII under abiotic stresses including HL illumination. The phosphorylation/dephosphorylation cycle along with subsequent degradation of photodamaged D1 protein to be replaced by the insertion of a newly synthesized copy of D1 into the PSII complex, is the core function of the PSII repair cycle. The exact mechanism of this process is still under discussion. We describe the recent progress in identifying the kinases, phosphatases and proteases, and in understanding their involvement in the maintenance of thylakoid structure and the quality control of proteins by PSII repair cycle during photoinhibition. © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Developmental stage-dependent differential gene expression of superoxide dismutase isoenzymes and their localization and physical interaction network in rice (Oryza sativa L.)

Superoxide dismutase (SOD) isoenzymes are essential for scavenging excess reactive oxygen species in living organisms. So far, expression pattern of SOD isoenzymes genes along leaf development plus their sub-cellular localization and physical interaction network have not yet been clearly elucidated. Using multiple bioinformatics tools, we predicted the sub-cellular localizations of SOD isoforms and described their physical interactions in rice. Using in silico approaches, we obtained several evidences for existence of seven SOD genes and a SOD copper chaperone gene. Their transcripts were differentially expressed along with different developmental stage of rice leaf. Finally, we performed quantitative real time-polymerase chain reaction (qRT-PCR) to validate in silico differential expression pattern of SOD genes experimentally. Expression of two cytosolic cCuZn-SODs was high during the whole vegetative stage. Two plastidic Fe-SODs were found and their expression levels were very low and started to increase from the late vegetative stage. Their expression patterns were very similar to each other, indicating the formation of heterodimer. However, their expression patterns are different from those for Arabidopsis Fe-SODs. The expression of pCuZn-SOD was very high in the early developmental stage, but qRT-PCR results were different, which remains for further study. From the results on the differential expression of SOD genes, we can understand the role of each SOD gene and even predict their role under certain circumstances based on in silico analysis. © 2013 The Genetics Society of Korea.1