Cai Y  et. al. (1993) “”Biological and Chemical Investigations of Dragon’s Blood from Croton Species of South America” Part 2. Diterpenes from Croton lecheri.” Phytochemistry 32(3), 755-760. 

Abstract: The chloroform extract of Croton lechleri sap was chemically examined, and the major constituents characterized by mass and NMR spectroscopy. In addition to a number of known compounds, such as 1,3,5- trimethoxybenzene, 2,4,6-trimethoxyphenol, 3,4-dimethoxyphenol, 3,4-dimethoxybenzyl alcohol, 4-hydroxyphenethyl alcohol and its acetate, sitosterol, sitosterol-small beta, Greek-Image-glucopyranoside and small beta, Greek-sitostenone, four diterpenoids were isolated from Croton lechleri bark, and two of them were found to be novel compounds possessing a clerodane skeleton. Their structures were unequivocally elucidated by extensive use of NMR spectroscopy. They were termed as crolechinol and crolechinic acid, respectively. The presence of these diterpenoids as minor constituents in the sap was confirmed by TLC profiles and NMR spectra.