Preparation of CRRP methanolic and water extract

The rhizomes of C. rotundus were cleaned from dust and foreign materials by hand and separate other parts of the plant, washed with water and then distilled water, dried at room temperature and then crushed by electrical machine into a fine powder and kept in polyethylene bags. To prepare methanolic and water extracts, 30 g of CRRP was extracted with either 300 ml methanol–water (4:1, v/v) or 150 ml of ddH₂O, at room temperature (25 °C) for 5–8 h using an orbital shaker. The extract was then filtered through filter paper and centrifuged (Hettich Zentrifugen, Tuttlingen, Germany) at 4000 × g for 10 min. The supernatant was concentrated under reduced pressure at 40 °C for 3 h using a rotary evaporator (IKA-WERKE-RV06ML) and kept at 4 °C until used for analysis.