Rose: A natural indicator and herbal antioxidant
Dr. Rojita Mishra, Lecturer in Botany
Rose is one of the most important ornamental flower immensely loved world wide due to its fascinating beauty, mesmerizing fragrance and preventive and cosmetic medicinal benefits. The German chemist Richard Willstätter  made the first breakthrough towards the understanding of the chemical structure of plant pigments and how colors could vary from plant to plant. He demonstrated that anthocyanins are glucosides, which are responsible for pigmentation. He also showed that the color of a plant doesn’t depend only on the pigment’s structure but also the plant’s sap or precisely its physiological pH and the concentration of the pigments themselves. Rose flower color is primarily composed of structurally simple cyanidin 3, 5-diglucoside. Acid-base indicators are commonly employed to mark the end of an acidbase titration or to measure the existing pH of a solution. Anthocyanins show remarkable change in color with the change in pH due to this property it gives an opportunity to use it as an acid base titration indicator rather than the conventional indicators like Phenolphthalein and methyl orange which are chemical based and may cause health hazards. The methanolic extracts of rose flower petals can be used as indicators in acid base titrations. The isolation of pure compounds responsible for indicator activity can facilitate better understanding of the underlying principle of indicators and new theories of indicators could be established . An antioxidant is a molecule capable of inhibiting the oxidation of other molecules. Antioxidants terminate chain reactions by removing free radical intermediates and inhibit other oxidation reactions. They do this by being oxidized themselves, so antioxidants are often reducing agents such as thiols, ascorbic acid or polyphenols.  Rose hips are the berry-like fruits of the rose bush left after the bloom dies. Rose hips have a tangy, fruity flavor similar to that of cranberries. The fruits are best harvested after the first frost, which makes them turn bright red andslightly soft. Rose hips contain high concentration of ascorbic acid. Completely ripe fruits contain ash, crude oil, crude energy, crude fiber, crude protein, ascorbic acid, dimethyl sulfite and minerals including K, P, Mg, Ca and Fe .
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