The genus Cajanus (Family: Fabaceae) consists of approximately 37 species, and Cajanus cajan (C. cajan) is a significant member of the genus. It is a commercial legume crop widely grown in sub-tropical and semi-arid tropical areas of the world. C. cajan is well known for its folk medicinal uses to treat various disorders, such as toothache, dizziness, diabetes, stomachache, female ailments and chronic infections. These properties have been linked to the presence of several value-added nutritional and bioactive components.
1. Botanical Description
1.1. Geographical Distribution and Taxonomy
C. cajan is a perennial drought resistance legume commonly cultivated in the sub-tropical and semi-arid tropical areas of the world
[12,13][1][2]. India is the prime producer, corresponding to approximately 90% of the total global production. It has also been found since ancient times in Africa, Caribbean, Southeast Asia, and Egypt and has been grown at a wide range of altitudes (up to 3000 m)
[8][3].
C. cajan is from the Genus
Cajanus, Family
Fabaceae, Order
Rosidae, Class
Magnoliopsida, and Kingdom
Plantae [7][4].
1.2. Cytology
The cytological analysis of
C. cajan showed that it is diploid having 2n = 2x = 22 chromosomes with an average length of 5.73 ± 1.15 µm up to 10.92 ± 2.69 µm and dominantly metacentric in shape, consisting of 14 metacentric and 4 submetacentric chromosomes
[14][5].
C. cajan has a genome of size 858 mega-base pairs
[15][6]. In the comparative genetic characterization of wild and cultivated
C. cajan genotypes, the cultivated species present maximum polymorphic loci
[6][7].
1.3. Morphology
From a morphological point of view,
C. cajan is a short-lived shrub with erect stems of 1–2 m height
[16][8]. Its roots are finely nodulated, lateral and deep rooted of up to 3 m, possessing a root system having a central taproot with several secondary and lateral branches. The branching pattern in
C. cajan is determined based on the habitat, spacing and plant genotype. The leaves are lanceolate to elliptical in shape and size, ranging from 6 to 17 cm in length and are around the same breadth. The flowers are usually, yellow to orange in color, present a long peduncle of 1–8 cm long and terminal or axillary racemes (4–12 cm). Calyx: gamosepalous with 5 lobes, Corolla: zygomorphic and bright yellow, Androecium: 10 stamens (4 with short filaments and 6 with long filaments), Gynoecium: ovary (superior, pubescent, 2–9 ovules and monocarpellary), style (long, filiform and glabrous), stigma (incurved & thickened), Seeds: spherical or lens shaped
[8][3].
2. Biological Applications
With the growth of world’s economy and enhancement in people’s living standard, several chronic diseases, like neurological, metabolic, inflammatory, cerebrovascular and cardiovascular disorders have increased rapidly
[46][9]. Natural products are widely recognized for their biological or pharmacological potential since ancient times, and recently the interest in their study has re-emerged as upcoming drug candidates. Globally, around 50,000 plants have shown potent therapeutic potentialities
[47][10]. According to pharmacological studies,
C. cajan leaves have various bioactivities, including antioxidant, antiplasmodial, anticancer, hypoglycemic, insecticidal, neuroprotective and antimicrobial activities
[37,48][11][12]. Moreover, the molecular regulatory mechanism of few biological applications/activity are briefly summarized in
Table 81. The most relevant therapeutic applications of
C. cajan briefly described below and presented in
Figure 21.
Figure 21.
Different biological applications of
Cajanus cajan
.
Table 81.
Molecular regulatory mechanism of few biological activities of
Cajanus cajan
.
S. No. |
Biological Activity |
Isolated Compounds/Extracts |
Biological Activity |
Reference |
1 |
Hypocholesterolemic |
Methanolic extract |
↑ LDRL; ↓PCSK9 mRNA |
[49][13] |
2 |
Antidepressant |
Cajanin stilbene acid |
↓ Kynurenine pathway |
[50][14] |
3 |
Neuroprotective |
AgNP |
↑ Proline; ↑ Glyoxalase; ↑ Pyrroline-5-carboxylate synthetase gene. |
[51][15] |
4 |
Antidepressant |
Fluoride exposure |
↓ Growth and membrane stability index; ↑ Reactive oxygen species; ↑ Malondialdehyde; ↑ Glutathione; ↑ Lipoxygenase. |
[51][15] |
5 |
Antioxidant |
Hexane extract |
↓ AChE; ↓ BChE; ↓ α-AMYLASE; ↓ α-glucosidase. |
[52][16] |
6 |
Antidiabetic |
Methanolic extract |
↓ Fasting blood sugar |
[53][17] |
7 |
Anticancer |
Betulinic acid, genistin, orientin and vitexin |
↓ Inhibit the Histone deacetylases enzyme |
[54][18] |
8 |
Antimitotic |
- |
↓ Decrease the percentage of Sea urchin embryonic cells |
[55][19] |
9 |
Anticancer |
Cajanin stilbene acid |
↓ Inhibit several human kinases, ↓ serine/threonine-protein kinase WNK3 |
[56][20] |