Pressurized liquid extraction of bioactive compounds from Taiwan pines

摘要

An experiment combining the Taguchi methodology with the response surface methodology to optimize the Pressurized Liquid Extraction (PLE) of proanthocyanidins from Taiwan pines was conducted. A L-18 orthogonal array was selected to investigate the total yield and the amount of proanthocyanidins. Experimental results showed that the extraction temperature most significantly affected the efficiency of extraction, but that a higher temperature also caused decomposition of bioactive components. Optimum conditions were identified as 20% EtOH, 140degreesC, 750 psig, and 1.5 h. The PLE total yield, proanthocyanidins content and total flavonoids were 2.09, 2.07, and 2.01 times greater than those obtained using a 50% EtOH conventional extraction method. Hot pressurized extraction has the advantages of low energy and high yield of bioactive compounds. The antioxidant activities of several extracts from two Taiwan pine-needles were individually evaluated for scavenging of DPPH free radicals and superoxide anion radicals, and for the inhibition of lipid peroxidation. The results revealed that both PLE M (Pinus morrisonicola) and PLE T (Pinus taiwanensis) extracted from two fresh pine needles scavenged 78.91% of DPPH free radicals. Air-dried pine needles also strongly inhibited superoxide anion radicals. The purification of four anthocyanidins from a PLE T extract was initially tested using HP-20 resin solid phase extraction and showed little enhancement. The isolation, purification and antioxidative mechanism of active components from pine needles need to be further investigated.