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Abstract :
Psidium guajava Linn. Family- Myrtaceae (guava) is a short tree or shrub and folk medicinal plant. It is found in all over India. Each part of the guava tree is useful and has biological importance. Many phytochemicals are present in guava leaves such as flavanoids, alkaloids, tannins, saponins, glycosides, oil and fats, steroids, phenols, proteins, carbohydrates. It is used in various diseases like cough, diabetes, cardiac diseases, diarrhea, wound healing. Guava has various biological activities like antispasmodic, antimicrobial, hepato-protective, antioxidant, anti-diarrheal, anti-inflammatory, anti-allergy. Guava leaves contain quercetin in higher amount (2.15%), which gives antibacterial and antioxidant activity. Antioxidant activity of guava leaves is checked by various methods such as Oxygen Radical Absorbance Capacity using Flourescien (ORAC-FL), Hydroxyl Radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Nitric Oxide Scavenging Activity, Nitrite Scavenging Activity, Reducing Power Assay. Guava leaves show better antimicrobial activity against fungal strain, gram positive, gram negative bacteria, yeast, moulds, bacteria isolated from urine samples, seabob shrimp and different microbial species such as Escherichia coli, Salmonella enteritidis, Bacillus cereus, Staphyllococcus aureus, Saccharomyces cerevisiae, Aspergillus niger, Vibrio and Aeromonas species, Lactobacillus acidophilus, Acne vulgaris, peridontal pathogens. Guava leaves are also reach in phenolic and flavanoid content.
Keywords : Antimicrobial activity, Antioxidant activity, Psidium guajava L.
Introduction :
Guava (Psidium guajava Linn. Family-Myrtaceae ) is a tropical and subtropical tree or shrub. It is native to Mexico, America. Guava is known for different names in different regions, in English Guava; in Combodia Trabeksrok; in French Araca, Aracaiba; in Maharashtra Peru; in Gujrat Jamrud; in Assam Madhuriam; in Deccan Guava or Jam or Laljam or Safedjam. Height of the tree is up to 7 to 10 m high. Bark of the tree is smooth, pale pinkish brown or buff with grey patches. Stem is irregularly fluted when old. Leaves are opposite, about 10-15 cm long, elliptic or oblong in shape. Flowers are white in color, 2.5-3.8 cm in diameter. Fruit is globose or pyriform berry 5 cm length or more. Stem, bark, roots and leaves are astringent. Fruit is laxative (1),(2).
It contains various phytochemicals in different extracts describe in Table 1 (12), (13), (15), (16). Concentration of phytochemicals shows in Table 2 (14). Fruit contains vitamin A, vitamin C, iron, phosphorus, calcium and minerals. Quercetin...