Diospyros leucomelas

Several examples of bioassay-guided isolation are given in the literature. Recio et al [47] used a topical irritant agent to track the activity during the isolation of the anti-inflammatory triterpenes from Diospyros leucomelas, whereas Cuellar et al. [48] employed a combined system of in vivo and in vitro experiments, consisting of the inhibition of an enzyme activity Fig. (1) . Other authors prefer in vitro models. Ammon and Safayhi [49] used the inhibition of leukotriene formation in rat peritoneal neutrophils to isolate the boswellic acids of gum resin exudate of Boswellia serrata, whereas Takaishi et al. [42] studied the inhibition of interleukin-1 secretion, and Jain et al. [50] studied the in vitro inhibition of phospholipase A2 activity. The main results of these studies are summarised in the pharmacological activity section of this chapter. 

In a comparative study on the anti-inflammatory activity of the Diospyros leucomelas (Ebenaceae) principles and other readily available triterpenoids administered at 100 mg/kg p.o., betulinic acid showed the highest activity (45% inhibition) 3h after carrageenan injection [47]. Erythrodiol had a more durable effect, inducing a 40% inhibition after 5 h [69]. After comparing the variable effects observed on this model, it was concluded that the presence of a primary alcohol or carboxylic acid function at C-27 or C-29 is clearly positive. 

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