2.2.2. Hot water infusion
Ten grams of the powdered samples were steeped in 400 ml of hot water at 95 ◦C for 10 min. The infusion obtained was filtered through Whatman No. 1 filter paper under vacuum and immediately cooled to room temperature. Further, the infusion was frozen and dried in a freeze dryer (Model 7754511, Labconco Corporation,Kansas City, USA) to a dry mass [obtained yield: 37.48 ± 0.81%]. The dried extract was kept at 4 ◦C in an airtight container until further analysis.
2.3. Hydro-distillation of essential oils
Steam distillation was employed for obtaining essential oils from the flower buds of P. suffruticosa. In brief, about 50 g of freeze dried samples were coarsely ground in a mortar and pestle and were placed inside a round-bottom flask. The flask was filled with distilled water and boiled using heating mantel. The sample was heatdistilled for 2 h and the distillate was extracted 4 times with 30 ml aliquots of diethyl ether. Anhydrous sodium sulphate was added to dry the organic layer and remove moisture. After drying, the solvent was decanted into a clean container and dried by flushing with nitrogen gas in a fume hood. The resultant oil was transferred to amber coloured glass vials to prevent exposure to light. Further, the vials were tightly closed, sealed with parafilm, and keptin a refrigerator at 4 ◦C until further analysis. The mass of the oil obtained was recorded and the amount extracted was expressed as percentage on a weight per weight (w/w) basis.