Use of ethanolic extract of Lantana camara L. flowers as pH indicator

Abstract

Anthocyanins are the flavonoid derivatives; widespread in the plant kingdom; imparting most of the brilliant colours like orange, red, pink, purple and blue; observed mostly in fruits, flowers and leaves (Zheng et al., 2011). Some of the naturally occurring anthocyanins of plants are cyanidin, peonidin, malvidin, delphinidin, pelargonidin and petunidin (Liliana et al., 2012). Chemically, the anthocyanin has a flavylium nucleus attached to one or more sugar residues, which may be Dglucose, D-galactose, L-rhamnose, D-xylose, and D-arabinose, are 3-glycosides or 3,5-di-glycosides (Miguel, 2011). Apart from being a natural colorant, anthocyanins have gained considerable research interest due to health benefits shown as a results of their antioxidant properties. Several times, antioxidants activity of anthocyanins have been demonstrated using several models (Miguel, 2011). Lantana camara L. (Figure 1) is an ornamental but notorious weed belong to family Verbenaceae (Patil and Kumbhar, 2017). It bears the flowers of colour ranging from yellow-white or pink to deep red or purple. (Huang et al., 2009) proved the presence of pigments, identified as 3-glucoside, 3,5-diglucoside and 3malonylglucoside of cyanidin, and 3,5-diglucoside and 3-malonylglucoside of peonidin in flowers (Huang et al., 2009) (Figure 2). An acid-base indicator is a compound which changes color according to change in pH. For synthetic acid-base indicators, it has been reported that they may have carcinogenic effect (Dunnick and Hailey, 1996). In addition, some of these synthetic indicators exhibited toxic effects such as pulmonary edema, diarrhea, hypoglycemia and pancreatitis and they can result in abdominal cramps, skin rash, eruptions, erythema, and epidermal necrosis and cause environmental pollution (Pathade et al., 2009; Abugri et al.,

Anthocyanin-Functionalized Contact Lens Sensors for Ocular pH Monitoring

“…The chemical structure of anthocyanins consists of a flavylium nucleus attached to one or more sugars, such as d -glucose, d -galactose, l -rhamnose, and d -arabinose. 2 The chemical stability of anthocyanins is influenced by pH, which induces a color shift from red in acidic conditions to blue in basic conditions. Besides their use as natural dyes, anthocyanins have shown antioxidative and antimicrobial properties.…”

“…Primary anthocyanins found in nature include cyanidin, peonidin, delphinidin, and petunidin. The chemical structure of anthocyanins consists of a flavylium nucleus attached to one or more sugars, such as d -glucose, d -galactose, l -rhamnose, and d -arabinose . The chemical stability of anthocyanins is influenced by pH, which induces a color shift from red in acidic conditions to blue in basic conditions.…”