Chlorophyll was extracted using ultrasonics [16]. Scraped bamboo epidermis chips were ground to powder (particle diameter < 0.7 mm) with a vibration mill (MFCSI, Janke & Kunkel Co., Germany). Bamboo epidermis powder (250 mg) was added to a sample vial containing 5 ml acetone. After extraction using an ultrasonic machine for 3 min, the solution was filtered through a 3G4 filter cup and the filtrate was analyzed by ultraviolet-visible (UV–vis). The absorption spectrum of chlorophyll was recorded over the range between 350 and 750 nm at a scanning speed of 400 nm/min using an ultraviolet-visible spectrophotometer (Jasco V-550, Japan). Each experiment was performed in triplicate and the chlorophyll content was then calculated using the specific equations for acetone and DMSO, respectively [7].