猜错了 QQ
原文本来是写永久花成分
"意大利酮II (可能是5, 7, 10-trimethylundec-9-en-4, 6-dione，2.6–6.9%)"
后来发现有文献写出结构式
https://bit.ly/2KvvDBd
Ascrizzi, Roberta & Flamini, Guido & Fraternale, Daniele. (2017). The
antiaging properties of Helichrysum italicum (Roth) G.Don essential oil:
collagenase and elastase inhibition activities.
结构是 2,4,6,9-tetramethyl-8-decene-3,5-dione 才对
原文会再同步更正～