African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12268

Full Length Research Paper

Subcritical water extraction of bioactive compounds from dry loquat (Eriobotrya japonica) leaves and characterization of triterpenes in the extracts

Erasto Mlyuka
  • Erasto Mlyuka
  • State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
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Shuang Zhang
  • Shuang Zhang
  • State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
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Zongping Zheng
  • Zongping Zheng
  • State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
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Jie Chen*
  • Jie Chen*
  • State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
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  •  Received: 02 March 2016
  •  Accepted: 06 May 2016
  •  Published: 01 June 2016

Abstract

Medicinal properties of loquat leaf extracts (LLEs) are associated with their constituents of phenolic compounds and triterpenes. In this study, the efficacy of subcritical water extraction (SWE) technique was assessed by comparing with conventional solid-liquid extraction (CE) and Soxhlet extraction (SE). Results showed that the highest yields of total polyphenols were 82.7 ± 1.5 mgGAE/g leaf weight (LW), total flavonoids (54.1 ± 4.1 mgQE/g LW) and total triterpenoids (37.5 ± 3.2 mgUAE/g LW) were obtained by SWE compared to total polyphenols (61.8 ± 3.3 mgGAE/g LW), total flavonoids (43.2 ± 0.6 mgQE/g LW) and total triterpenoids (28.7 ± 2.3 mgUAE/g LW) extracted by SE and total polyphenols (50.3 ± 1.8 mgGAE/g LW), total flavonoids (40.4 ± 2.1 mgQE/g LW) and total triterpenoids (22.9 ± 3.2 mgUAE/g LW) obtained by CE. The extraction efficiency of triterpenes using SWE was about 1.7 times higher than those obtained using traditional extraction methods, and their main structural pattern of the cured extracts was comparable to the extracts obtained using traditional extraction methods.The infrared spectra obtained from the three extraction techniques appeared identical, but the variation in the intensity of the peak of absorption was visible among the three extraction techniques. The similarity of the infrared spectral pattern (peak coincided peak by peak) implies that the triterpenes in the extract obtained by the three techniques were identical by LC/MS. The findings of this study have demonstrated that SWE can be employed as an alternative green extraction technology to get important phytochemicals from plant sources.

Key words: Chinese loquat leaf, Eriobotrya japonica, subcritical water extraction, triterpene. 

Abbreviation

LLEs, Loquat leaf extracts; CA, corosolic acid; DLL, dry loquat leaves; PTTs, pentacyclic triterpenoids; SWE, subcritical water extraction; CE, conventional solid-liquid extraction; UA, ursolic acid; LC/MS, liquid chromatography-mass spectrometry; SE, soxhlet extraction; TPC, total phenolic contents; OA, oleanolic acid; TFC, total flavonoid contents; FT-IR, fourier transform infrared spectrometer.