Table 2: Herbal materials used in managing SCA and its probable modes of action.

Herb/referenceProbable general effect/mode of action/phytochemical constituents

Fagara zanthoxyloides  
(root) [27, 28]
Three isomeric divanilloylquinic acids (burkinabin A, burkinabin B, and burkinabin C) were identified as the likely antisickling agents. But some workers have proposed coumarins, vanillic acid, parahydroxybenzoic acid, and paraflurobenzoic acid.

Carica papaya—(unripe fruit or leaf) [2931]Antisickling effects of 87% inhibitory and 74% reversal activities were obtained from the 5-day fermentation of unripe fruit of C. papaya at 2.5 mg per mL of water. Methanol extract had 64% inhibitory and 55% reversal activities while the chloroform extract was inactive. Phenylalanine, tyrosine, and glycine were thought to be responsible.

Garlic  
(bulb) [32]
The basis is unknown, but allicin in garlic, is a potent stimulus of TRPV1 as mentioned in Section 4 (Biochemical Bases for Herbal Management of SCA). Moreover, garlic is used in many infective conditions especially respiratory infections in SCA.

Hymenocardia acidai   
(leaf) [33]
Mpiana et al. [33] related the anti-SCA activities of H. acida to anthocyanins.

Cajanus cajan   
(seed) [34, 35]
Phenylalanine is thought to be the most active principle in Cajanus cajan seed—a component of Ciklavit antisickling phytomedicine, developed in Nigeria by two professors, Ekeke and Shode [34].

Khaya senegalensis   
(stem bark/leaf) [36]
Fall et al. [36] attributed the anti-SCA effects of K. senegalensis to limonoids.

The herbs Niprisan:
(1) S. bicolor   
(2) P. osun  
(3) Clove   
(4) P. guineense  
[3740]
The bases for the actions of Sorghum bicolor and Pterocarpus osun are unknown, but they are rich in brightly coloured red/orange flavonoids. They probable act as hematonics especially if they contain folic acid or its analogues. Given their blood red colour, the “Doctrine of Signatures” as mentioned elsewhere [16, 17] may have influenced their inclusion by Yoruba sages of old. It had been supposed that the principles in Niprisan that mitigate, palliate, or reduce the frequency of SCA crisis [18] probably reside mainly in clove and P. guineense [14].

Clove is Eugenia caryophyllata, which, like P. guineense, contains principles that impact SCA crisis. Notably, the isomeric divanilloylquinic acids of Fagara zanthoxyloides contain the vanillyl group as do the vanilloids of clove and P. guineense. A discussion of these principles is presented in Section 4.