Abstract
Phalaenopsis spp. is the most commercially and economically important orchid, but their plant parts are often left unused, which has caused environmental problems. To date, reports on phytochemical analyses were most available on endangered and medicinal orchids. The present study was conducted to determine the total phenolics, total flavonoids, and antioxidant activity of ethanol extracts prepared from leaves and roots of six commercial hybrid Phalaenopsis spp. Leaf extracts of “Chian Xen Queen” contained the highest total phenolics with a value of 11.52 ± 0.43 mg gallic acid equivalent per g dry weight and the highest total flavonoids (4.98 ± 0.27 mg rutin equivalent per g dry weight). The antioxidant activity of root extracts evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay and β-carotene bleaching method was higher than those of the leaf extracts. Eleven phenolic compounds were identified, namely, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, vanillin, ferulic acid, sinapic acid, p-coumaric acid, benzoic acid, and ellagic acid. Ferulic, p-coumaric and sinapic acids were concentrated largely in the roots. The results suggested that the root extracts from hybrid Phalaenopsis spp. could be a potential source of natural antioxidants. This study also helps to reduce the amount of this orchid waste in industrial production, as its roots can be exploited for pharmaceutical purposes.
Highlights
Vegetables, spices, and herbs contain important natural substances such as antioxidants.Several studies have dealt with antioxidant activity to find new sources of natural antioxidants to be used in foods, cosmetics, medicine, and other purposes [1,2]
Phenolic compounds are one of the major chemical classes of plants’ secondary metabolites. They play an important role in the defense of plants against pathogens, diseases, parasites, and predators [24]
They involve in a number of physiological mechanisms such as antioxidant activity
Summary
Vegetables, spices, and herbs contain important natural substances such as antioxidants. Several studies have dealt with antioxidant activity to find new sources of natural antioxidants to be used in foods, cosmetics, medicine, and other purposes [1,2]. Antioxidants play an important role in health care to prevent and scavenge free radicals; alleviate chronic diseases and degenerative ailments such as cancer, autoimmune disorders, hypertension, atherosclerosis; and delay the ageing process [3,4,5,6,7,8,9]. Of all the plant secondary metabolites, phenolic compounds have been extensively studied and are commonly used as antioxidants for a wide range of applications [10]. Investigation of new and safe antioxidants from natural sources has become very important for food and medicinal functions [11].
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