EFFECTS OF DRYING METHODS ON THE ANTIOXIDANT PROPERTIES OF PHENOLIC-RICH EXTRACTS OF AFRICAN MISTLETOE (LORANTHUS BEGWENSIS L.) LEAVES FROM ALMOND AND KOLANUT HOST TREES.

Abstract

African mistletoe (Loranthus begwensis L.) has been employed in sub-Sahara African folklore for the treatment of many degenerative diseases owing to its strong antioxidant properties. It has been reported that drying methods play an important role in herbs production. This study sought to investigate the most appropriate drying method by assessing the influence of these drying methods on the antioxidant properties of the leaves. Fresh leaves obtained from almond and kolanut host trees were subjected to oven drying, sun drying and air drying respectively after which the phenolic extraction was carried out. The influence of these drying methods on the total phenol and total flavonoid content as well as antioxidant properties (NO*, OH*, DPPH* scavenging and Fe2+ Chelating abilities) were assessed using standard methods. The total phenol ranged from 19.38 mg.GAE/100 g (Kolanut air-dried) to 39.47 mg.GAE/100 g (Almond oven-dried), while the flavonoid content ranged from 8.70 mg.QUE/100 g (Almond air-dried) to 21.81 mg.QUE/100 g (Almond oven-dried). In addition, all extracts scavenged DPPH [786.16 µg/ml (Almond oven-dried) to 1179.25 µg/ml (Kolanut air-dried)], NO [584.11 µg/ml (Almond oven-dried) to 1054.85 µg/ml (Kolanut air-dried)] and OH [404.86 µg/ml (Almond oven-dried) to 784.93 µg/ml (Kolanut air-dried)] radicals in dose-dependent manner as well as chelate Fe2+[377.64 µg/ml (Almond oven-dried) to 593.82 µg/ml (Kolanut air-dried)]. This study revealed that oven drying is the best method for mistletoe leaves obtained from almond host tree while sun drying is the best for mistletoe leaves obtained from Kolanut host tree as exemplified by their radical scavenging abilities and total phenolic compounds. Thus, diversity in drying methods leads to different loss of phenolic compounds and antioxidant property, suggesting that each plant family needs a special drying metho