**2.2 Chemical constituents**

There are 212 bioactive chemicals found in *A. muricata*, per the studies. Acetogenins are the most common chemicals, followed by alkaloids, phenols, and other active ingredients. The leaves and seeds are the most frequently investigated plant parts, probably because they are the most often used.

More than 200 bioactive compounds have been isolated from *A. muricata*, including six types of acetogenins, various alkaloids (mostly isoquinolines,

#### **Figure 4.**

*Geographical distribution of A. muricata [1]. native, introduced. Note: South American native plant species, west, central Africa, and south Asia introduced plant species.*

aporphines, and protoberberines, notably reticuline and coreximine), phenols (e.g., quercetin and gallic acids), and other compounds, including sesquite rpene derivatives. At least 50 pharmacological studies have already been conducted, with two-thirds in vitro and one-third in vivo studies involving mice models. Coria-Tellez et al., 2017 have recently published extensive studies of the above.

There are six prominent phytochemicals which have been isolated from *A. muricata* plant species as alkaloid, annonaceous acetogenin, megastigmane, flavonol triglycoside, phenolic, cyclopeptide.

Annonaceous acetogenins are one class of phytochemicals exclusive to the annonacae plant species [10].

#### **2.3 Medicinal uses**

A number of medicinal uses have been reported across the globe ranging from the use of leaves, bark, roots, fruits to seeds of *A. muricata* [11].

The most widely used preparation in traditional medicine is the decoction of bark, root, seed or leaf but applications are varied. In a number of tropical sub-Saharan countries such as Uganda, all parts are used to treat malaria, stomachache, parasitic infections, diabetes [12], and cancer [13].

The use of graviola leaves extract can cure malaria in tropical countries like Cameroon, Togo, and Vietnam [14–16]. In Ghana, *A. muricata* and some other plants are decocted into a mixture and used in bath for pregnant mothers prior to birth [17].

In west Africa, *Annona muricata* is mostly used as food as fruit because of its antioxidant properties which have been evaluated in fresh or frozen pulp, juice, and fresh or dried leaves [12].

Lately, the medicinal uses of *A. muricata* leaves included treatments for hypertension [11–19], diabetes and cancer.

Annona muricata *(Graviola): Nutraceutical in COVID-19 DOI: http://dx.doi.org/10.5772/intechopen.104139*

According to Linn Churchill et al., (1980) *Annona muricata* Fruit and fruit juice are taken for worms and parasites, to cool fevers, to increase mother's milk after childbirth, as an astringent for diarrhea and dysentery. The crushed seeds are used against internal and external parasites, head lice. The bark, leaves, and roots are considered as sedative, ulcer treatment, hypotensive, and nervine, and a tea is made for various disorders towards those effects.

Coria-Téllez et al., (2018) explained that in fruits and roots of *annona murricata* contains acetogenins proved to have anticarcinogenic effect.

Acetogenins have been reported to show significant antiviral activities against herpes simplex virus-I (HSV-I) (Padma et al., 1998), herpes simplex virus-II (HSV-II) (Betancur-Galvis et al., 1999), human papillomavirus (HPV) (Donne et al., 2017), hepatitis C virus (HCV) (Apriyanto et al., 2018), dengue virus type 2 (DENV-2), human immunodeficiency virus-I (HIV-I) (van de Venter et al., 2014; [12]).
