广西北海拉关木挥发物的ATD-GC/MS分析及安全性评价

Analysis of volatiles from Laguncularia racemosa in Beihai, Guangxiby ATD-GC/MS and evaluation on safe property of the tree

关键词:  拉关木, 嗅觉, 活体, 动态顶空, 全自动热脱附-气相色谱/质谱(ATD-GC/MS), 环境安全

Key words:  Laguncularia racemose, sense of smell, in situ, dynamic head-space, auto thermal-desorption cryo-trapping gas chromatography/mass spectrometry(ATD-GC/MS), environment safety

摘要:

速生红树植物拉关木具有优良的耐盐抗污染特性,但其自身吸收海水污染物后对周边环境及人类是否安全引人关注,尤其是该树种释放的挥发性成分在嗅觉方面是否安全有待评价。该研究以其活体无损伤幼龄及成年枝叶(无花、开花及带果状态)的挥发物为对象,用动态顶空密闭循环吸附捕集方式采集样品后,经全自动热脱附—气相色谱/质谱(ATD-GC/MS)联用分析。结果表明:拉关木挥发物由萜烯、酮、羧酸等化合物组成,其中萜烯所占比例最高,而最优势成分α-蒎烯在各试样中的相对百分含量均在3/4左右,β-水芹烯、β-蒎烯等其它萜烯也具有较高含量,为10%～15%及在5%以上,萜烯类成分的存在与有关红树植物提取物化学成分的文献报道相吻合。试样中的其它少量成分呈松木、冬青、柑橘、桉树等香韵,部分成分具有中等强度的香比强值(ASV),如莰烯(250)、苯甲醛(500)、苯乙酮(200)、壬醛(550)、水杨酸甲酯(450)等,部分成分的ASV值较低,如萜品油烯(异松油烯,120)、辛酸(100)、壬酸(100)、对伞花烃(80)等,但对总体气味均有一定的贡献度。 由于拉关木挥发物中的各种成分总体有益于人体健康,且在日用香料香精产品中可广泛应用。因此,该树种在嗅觉方面安全、无毒,适合沿海植被恢复、景观及“芳香化”营造等,应用前景良好。

Abstract:

Laguncularia racemosa is a fast growing mangrove plant with excellent properties of anti-salt and waste prevention. But its safety to the environment and human beings need to evaluate when it absorbs polluted materials from the sea water, especially the safety on sense of smell of those volatile compositions released from the tree. For these concerns, volatiles from both the juvenile and adult branches without flowers or fruits were collected. And for the latter, it was also sampled branches with flowers and fruits. These samples were all obtained from the cultivation base for mangroves in Beihai, Guangxi Zhuang Autonomous Reigion, China, which was a suitable afforestation farm for this mangrove plant with relatively high stability. Such volatiles mentioned above were captured in situ, i.e. from the living and undamaged tree, by dynamic head-space adsorption within a close and air circular system, using a set of portable apparatus which was easily available to experimental operation in the fields. Then, their chemical compositions were analyzed using auto thermal-desorption gas chromatography/mass spectrometry(ATD-GC/MS). The results showed that terpines, ketones, acids and other substances were detected in the tree volatiles, among which the highest content parts were terpines. In all samples, over 3/4 of the total volatile percentage was α-pinene, which shared the most preponderance of those compositions. Terpenes such as β-phellandrene and β-pinene were also with relatively high content, the former ranging nearly 10%-15% and the latter over 5%. It was concord with investigations on the constituents of those extracted chemicals from this tree and other mangrove plants such as Aegiceras comiculatum, as terpines were found in all of them. The other less compounds also contributed to the total smell at some point, providing fragrances as pine wood, holly tree, orange, eucalyptus and other vegetations, although they were various in aroma strong value of fragrance or odor(ASV). Some substances were considered as mid-strong ASV chemicals, such as camphene(250), benzaldehyde(500), acetophenone(200), nonanal(550), methyl salicylate(450)etc., and others were considered as low ASV chemicals, such as terpinolene(120), octanoic acid(100), nonanoic acid(100), p-cymene(80), etc. For its benefit to human health, L. racemosa is probably available to daily cosmetics and flavors by using the volatiles widely. Due to the safe and non-toxic smelling, the tree can be regarded as a prospective species for seashore vegetation rebuilding, coastal eco-restoration and landscape/fragrance environment making in the urban beaches.