**3.12. Malvaceae –** *Gossypium barbadense* **L.**

The sea island cotton or Egyptian cotton *G. barbadense* (**Figure 6**) is believed to have emerged in Peru as a cross between *G. herbaceum* L. and *G. raimondii* Ulbrich or *G. gossypioides* (Ulbrich) Standley. It is now widely cultivated in the warmer parts of the world, and is an important industrial and export product of Egypt, the West Indies, Sudan, Peru, and the USA.

Cotton is the soft white fibrous substance that surrounds the seeds of the plant and helps in the dispersal of the seeds [148]. It consists of 88–96% α-cellulose, 3–6% hemicellulose, and 1–2%

**Figure 6.** Malvaceae – *Gossypium barbadense* L. (from: https://goo.gl/images/NN46ra).

lignin [148]. Since about 2500 BC, the fibers are used for making sewing thread, yarn, cordage, and fishing nets, and more recently also for making coffee filters, paper, surgical dressings, and nitrocellulose-based explosives [148]. The seed oil can be incorporated in, among others, margarine and mayonnaise, but also in soaps, cosmetics, lubricants, and protective coatings [148]. The oil as well as other parts of *Gossypium* species contains the triterpenoid aldehyde gossypol that causes infertility in males [149]. Other constituents of *G. barbadense* are alkaloids, flavonoids, total phenols, cyanogenic glycosides, and saponins [148, 150].

processed to give food colorings. The seed oil can be used for cooking and the seeds are eaten roasted as a snack. However, *H. sabdariffa* seeds probably contain toxic substances and may be better used for manufacturing soaps and shrubs [154]. Young shoots, leaves, and calyces can be included in certain dishes, and fresh or dried calyces are used to prepare flavorful and slightly acidic herbal teas, refreshing beverages that may be carbonated, cock-

Plant-Based Ethnopharmacological Remedies for Hypertension in Suriname

http://dx.doi.org/10.5772/intechopen.72106

173

**Figure 7.** Malvaceae – *Hibiscus sabdariffa* L. (from: https://goo.gl/images/BRZcTZ).

Preparations from *H. sabdariffa* leaves, calyces, and roots are widely used in traditional medicines because of their presumed antimicrobial, antioxidant, anticancer, hepatoprotective, hypocholesterolemic, antidiabetic, diuretic, and antihypertensive properties [45, 155, 156].

The results from preclinical studies have associated the potential antihypertensive (and cardioprotective) properties of particularly tea made from roselle calyces with its abundant content of polyphenolic compounds such as chlorogenic acids [157], as well as flavonoid compounds such as kaempferol, quercetin, and anthocyanins [156, 158]. Chlorogenic acids (modestly) reduced an elevated blood pressure [157, 159]. Kaempferol may have a protective effect in heart diseases [160]. Quercetin caused the release of NO from vascular endothelium, increasing renal vasorelaxation and kidney filtration, stimulating diuresis and decreasing blood pressure [161]. And the anthocyanins may exert antioxidant effects which inhibit LDL oxidation, impeding atherosclerosis, an important cardiovascular risk factor [162]. Alternatively, anthocyanins may decrease blood pressure by inhibiting ACE activity [163]. These compounds, along with the flavonoids and the chlorogenic acids, have also been suggested to decrease hypertension by stimulating diuresis following modulation of aldosterone

However, comprehensive reviews and a meta-analysis suggest that the evidence for the use of *H. sabdariffa* preparations against hypertension is insufficient and recommend more highquality animal and human studies to demonstrate benefit from these substances in this condi-

Phytochemical and pharmacological studies supported some of these uses [155, 156].

tails with rum, as well as jams.

activity [164].

tion [162, 165, 166].

*G. barbadense* preparations are widely used in traditional medicine. In many African countries as well as the Guianas including Suriname, preparations from leaves, roots, and seed oil are used for treating a multitude of diseases ranging from eye affections, otitis media, bronchitis, and menstrual problems to malaria, convulsions, gonorrhea, leprosy, and hypertension [45, 51, 52, 55, 151]. Pharmacological studies have supported some of these folk medicinal uses [151, 152].

The presumption of a blood pressure-lowering effect of *G. barbadense* was supported by the dose-dependent hypotensive effect of a fraction of a crude leaf extract in laboratory rats [153]. The results from parallel studies with several agonists and antagonists of acetylcholine receptors suggested that this occurred through an action on the central nervous system comparably to that of the centrally acting α2 -adrenergic agonist clonidine [153]. On the other hand, an aqueous extract from *G. barbadense* leaves decreased the tension of isolated guinea pig aorta rings stimulated with phenylephrine (a selective α1 -adrenergic receptor agonist) by 15–35% [75], suggesting that it may lower an elevated blood pressure by decreasing the peripheral vascular resistance.

#### **3.13. Malvaceae –** *Hibiscus sabdariffa* **L.**

The roselle *H. sabdariffa* (**Figure 7**) probably originates from Africa and is presumably domesticated in Sudan about 6000 years ago. It was initially cultivated for its seed and later for its leaves and bright red colored calyces which are particularly in the USA and Germany

**Figure 7.** Malvaceae – *Hibiscus sabdariffa* L. (from: https://goo.gl/images/BRZcTZ).

lignin [148]. Since about 2500 BC, the fibers are used for making sewing thread, yarn, cordage, and fishing nets, and more recently also for making coffee filters, paper, surgical dressings, and nitrocellulose-based explosives [148]. The seed oil can be incorporated in, among others, margarine and mayonnaise, but also in soaps, cosmetics, lubricants, and protective coatings [148]. The oil as well as other parts of *Gossypium* species contains the triterpenoid aldehyde gossypol that causes infertility in males [149]. Other constituents of *G. barbadense* are alkaloids, flavonoids,

*G. barbadense* preparations are widely used in traditional medicine. In many African countries as well as the Guianas including Suriname, preparations from leaves, roots, and seed oil are used for treating a multitude of diseases ranging from eye affections, otitis media, bronchitis, and menstrual problems to malaria, convulsions, gonorrhea, leprosy, and hypertension [45, 51, 52, 55, 151]. Pharmacological studies have supported some of these folk medicinal

The presumption of a blood pressure-lowering effect of *G. barbadense* was supported by the dose-dependent hypotensive effect of a fraction of a crude leaf extract in laboratory rats [153]. The results from parallel studies with several agonists and antagonists of acetylcholine receptors suggested that this occurred through an action on the central nervous system comparably

aqueous extract from *G. barbadense* leaves decreased the tension of isolated guinea pig aorta

[75], suggesting that it may lower an elevated blood pressure by decreasing the peripheral

The roselle *H. sabdariffa* (**Figure 7**) probably originates from Africa and is presumably domesticated in Sudan about 6000 years ago. It was initially cultivated for its seed and later for its leaves and bright red colored calyces which are particularly in the USA and Germany



total phenols, cyanogenic glycosides, and saponins [148, 150].

**Figure 6.** Malvaceae – *Gossypium barbadense* L. (from: https://goo.gl/images/NN46ra).

uses [151, 152].

172 Herbal Medicine

vascular resistance.

to that of the centrally acting α2

**3.13. Malvaceae –** *Hibiscus sabdariffa* **L.**

rings stimulated with phenylephrine (a selective α1

processed to give food colorings. The seed oil can be used for cooking and the seeds are eaten roasted as a snack. However, *H. sabdariffa* seeds probably contain toxic substances and may be better used for manufacturing soaps and shrubs [154]. Young shoots, leaves, and calyces can be included in certain dishes, and fresh or dried calyces are used to prepare flavorful and slightly acidic herbal teas, refreshing beverages that may be carbonated, cocktails with rum, as well as jams.

Preparations from *H. sabdariffa* leaves, calyces, and roots are widely used in traditional medicines because of their presumed antimicrobial, antioxidant, anticancer, hepatoprotective, hypocholesterolemic, antidiabetic, diuretic, and antihypertensive properties [45, 155, 156]. Phytochemical and pharmacological studies supported some of these uses [155, 156].

The results from preclinical studies have associated the potential antihypertensive (and cardioprotective) properties of particularly tea made from roselle calyces with its abundant content of polyphenolic compounds such as chlorogenic acids [157], as well as flavonoid compounds such as kaempferol, quercetin, and anthocyanins [156, 158]. Chlorogenic acids (modestly) reduced an elevated blood pressure [157, 159]. Kaempferol may have a protective effect in heart diseases [160]. Quercetin caused the release of NO from vascular endothelium, increasing renal vasorelaxation and kidney filtration, stimulating diuresis and decreasing blood pressure [161]. And the anthocyanins may exert antioxidant effects which inhibit LDL oxidation, impeding atherosclerosis, an important cardiovascular risk factor [162]. Alternatively, anthocyanins may decrease blood pressure by inhibiting ACE activity [163]. These compounds, along with the flavonoids and the chlorogenic acids, have also been suggested to decrease hypertension by stimulating diuresis following modulation of aldosterone activity [164].

However, comprehensive reviews and a meta-analysis suggest that the evidence for the use of *H. sabdariffa* preparations against hypertension is insufficient and recommend more highquality animal and human studies to demonstrate benefit from these substances in this condition [162, 165, 166].
