**4.** *Asparagus laricinus Burch.*

*Vernacular names* **English:** Wild asparagus; **Afrikaans:** Bergkatbos, Bergkatdoring, Fynkatbos, Katdoring, Langbeenkatdoring; Zulu: Ibutha, Setswana: Lesitwana [13]. **Synonym:** *Protasparagus laricinus (Burch*.) Oberm.

### **4.1 Historical aspects**

*Phytochemicals in Human Health*

diverse conditions.

**2. Methodology**

**2.1 Search criteria**

**2.2 Data analysis**

properties" were used in the search.

It is estimated that three quarters of the world of mankind relies on herbal and traditional medicine as a basis for primary healthcare [4]. It was discovered that between 12 and 15 million South Africans still rely on more than 700 indigenous types of plants for the supply of their traditional herbal medicines [5]. Up to 60% of the South African population consults one of an estimated 200,000 traditional healers in rural areas [6]. These herbal medicines which are extracted from plants and used for medicinal purposes often result in acute toxicity. For example, it is estimated that between 8000 and 20,000 people die every year in South Africa due to the fact that these medicinal plants are used incorrectly [7, 8]. The Food and Drug Administration [FDA] indicates that both serious and moderate adverse events from many botanical and others traditional medicinal products are significantly underreported, and that the annual number of such cases is at least 50,000 each year [9, 10]. Different research studies to elucidate and validate the ethnobotanical value of medicinal plants have been conducted and reported by investigators world-wide, with findings that were established from the use of various methods, and also under

In this review study, five native Asparagus species (namely A*sparagus laricinus Burch.*, *Asparagus africanus Lam.*, *Asparagus officinalis L.*, *Asparagus racemosus Willd.* and *Asparagus densiflorus Kunth) Jessop*) were evaluated for their historical, etymological, morphological, phytochemical and pharmacological aspects. The findings of this review study are summarized, and the medicinal properties of the

Original articles, research papers published in journals and in PubMed central, Google scholars on plants of interest (*Asparagus laricinus Burch.*, *Asparagus africanus Lam.*, *Asparagus officinalis L.*, *Asparagus racemosus* and *Asparagus densiflorus (Kunth) Jessop)*, and medicinal uses were studied, and related articles and papers were also taken into consideration. The two species, *Asparagus laricinus Burch.* and *Asparagus africanus Lam.* were the first choice according to the research studies at the laboratory of authors for their pharmacological activities and toxicology. The other three species of interest were randomly selected from an enormous number of Asparagus species retrieved when the key words "Asparagus species with medicinal

The available literature was especially studied for historical, etymological, morphological, phytochemical and pharmacological aspects of *Asparagus laricinus Burch.*, *Asparagus africanus Lam.*, *Asparagus officinalis L.*, *Asparagus racemosus* and *Asparagus densiflorus (Kunth) Jessop*. Priority was given to ethnobotanical reports, laboratory work and clinical trials carried out on all five species. Finally, results

The genus Asparagus is an herbaceous plant comprising approximately 150 species

around the world which are comprised of herbs, shrubs and vines [11]. Asparagus

were obtained from all collected data and literature studied.

**3. Asparagus species with medicinal properties**

chosen Asparagus species are documented in this review study.

**208**

*Asparagus laricinus Burch.* is a very hardy, evergreen, shrubby Asparagus with fine, feathery foliage and silvery, zigzag branchlets. It has myriads of tiny white, nectar-rich flowers that develop during spring and summer. These flowers are fragrant and attract insects and birds. Birds in the garden are attracted by its bright red and black berries. It may be grown in the sun or semi-shade and is a very useful plant for a security hedge as it is extremely spiny. It is fire-resistant and, if the stems burn, it shoots quickly from the base. The new shoots can be eaten as a vegetable. It grows in sun or shade and in all types of soil except water-logged soils. It can grow up to 1.5 m. *Asparagus laricinus Burch.* is native to Botswana and South Africa, Lesotho and Swaziland. They are used to treat tuberculosis, sores, red water, uterine infection, general alignments, umbilical cord inflammation, and serve as a diuretic.

#### **4.2 Phytochemical active principals**

Roots and leaves of *Asparagus laricinus Burch.* had tannins, saponins, terpenes, steroids. However, only roots showed the presence of alkaloids [14], while leaves are devoid of alkaloids [15]. The leaves further had flavonoids, glycosides, steroids and carbohydrates. The stems are rich in saponins, tannins, and flavonoids, with a lack of steroids, glycosides and carbohydrates [15]. The *Asparagus laricinus Burch.* aqueous roots extract contained 4.2 g/l GAE (Gallic acid equivalent) total phenolic content, while leaves and stem aqueous extract showed the phenolic concentration of 0.572 mg/GAE and 0.277 mg/GAE, respectively. It was apparent that leaves had more phenolic content than the stem, and this was supported by the number of active phytochemicals identified from both parts of the plant. Fuku et al. [14] isolated and identified three compounds from the *Asparagus laricinus Burch.* roots: indole-3-carbinol, α-sitosterol and ferulic acid.

#### **4.3 Pharmacological actions**

Secondary metabolites produced by plants for plant protection do not only benefit plants, but they also have health benefits for human beings. These compounds

result in antimicrobial medicines [16], anti-inflammatory drugs, anticancer drugs, and plant-based anti-oxidants. Phytochemical screening was performed on the leaves and roots of *Asparagus laricinus Burch.*, and parts had tannins, saponins, terpenes, and steroids. However, only roots showed the presence of alkaloids. It was also shown that flavonoids which are known to have an ability to inhibit microbial growth also scavenge antioxidants. The leaf extract contained steroids, these being important compounds as sex hormones. Both leaves and stem extracts showed that they contain saponins, which ultimately has a suppressive effect on inflammation [17]. This is a main reason why *Asparagus laricinus Burch.* is used in traditional medicine. *In vivo* anti-inflammatory activity studies of this plant are being conducted in the Unit of Drug discovery, CUT [18].

Tannins are generally found in most plant parts: bark, wood, leaves, fruits and roots, and can have a toxic effect on filamentous fungi, yeasts and bacteria [19]. No alkaloids were found in this study. Leaf extracts further showed positive antibacterial activity on *S. aureus*, *S. saprophyticus*, *E*. *cloacae* and *B. subtilis*. Inhibition of *Staphylococcus aureus* by the *Asparagus laricinus Burch.* plant extract demonstrates huge potential for using this plant to extraction in the treatment of microbial infections, especially in the light of the growing antibiotic resistance in micro-organisms. The presence of phenols correlates with the antibacterial and antioxidant activities of the leaf extract of *Asparagus laricinus Burch*., as demonstrated by Ntsoelinyane and Mashele [15].

In recent times, there has been a growing interest in finding antioxidants which occur naturally to replace synthetic antioxidants, many of which are being restricted due to their carcinogenicity [20, 21]. Free radical scavenging molecules such as flavonoids, tannins, alkaloids, quinones, amines, vitamins and other metabolites have anti-inflammatory, anti-carcinogenic, antibacterial and antiviral activities [22]. *Asparagus laricinus Burch.* aqueous extracts of roots and leaves showed positive antioxidant activity with DPPH assay [15]. Flavonoids contain anion radicals and produce membrane bound enzymes [23]. This could be the reason for the mechanisms of antioxidative action of *Asparagus laricinus Burch.* leaf extract. The antioxidant that is found in the plant extract may also be due to polyphenols as phenolics being present [24]. The aqueous leaves extract of *Asparagus laricinus Burch.* produced significant activity as an antioxidant, and this could be due to the presence of ferulic acid; and as it is a known to protect cells from oxidative stress.

Using the Ames test on *Salmonella typhimurium* strains*:* TA97, TA98, TA100 and TA102 without any metabolic activation, Mashele and Fuku [25] evaluated the mutagenic and antimutagenic properties of the aqueous root's extracts of this plant. The extract was non-mutagenic towards all strains, had moderate inhibitory effect on TA100, and had low inhibitory effects on TA102 and TA97 [7]. Root aqueous extract showed an indirect mutagenic effect toward TA102 after metabolic activation, but not in TA97, TA98 and TA100. However, it was found that the Ames test, without S9 (liver extract of a rat, hamster or human) metabolic activation, could only detect direct mutagens, while S9 metabolic activation allowed the detection of indirect mutagens which were mostly caused by conjugation reactions of metabolic oxidation systems. Cytotoxicity activity on Vero cells was also elucidated. The cytotoxicity tests indicated no cytotoxic effect below 500 μg/ml concentration of the *A. laricinus Burch.* aqueous extract [7].

The phytoconstituents detected from *Asparagus laricinus Burch.* may have caused the cytotoxic activity, although their precise mode of action is poorly understood. Only a few compounds were isolated from the roots of *Asparagus laricinus Burch.*: indole-3-carbinol, α-sitosterol and ferulic acid. β-Sitosterol have numerous therapeutic and chemo-preventive uses in the medical field [26, 27]. Prostate cancer is being treated by Indole-3-carbinol [28]. Anticancer activity on breast (MCF7), renal (TK10) and melanoma (UACC62) using roots aqueous and ethanol extracts was

**211**

**5.** *Asparagus africanus Lam.*

*Vernacular names*

*Medicinal Properties of Selected Asparagus Species: A Review*

shown by Mashele and Kolesnikova [29], who revealed that ethanol extracts were very active while aqueous extracts were weakly active. However, ethanol roots extract only showed the presence of tannins while the aqueous roots extract showed a number of active phytochemicals. These results should be investigated further to elucidate the aforementioned difference. It may be that the presence of other active compounds somehow affected the ability of tannins by neutralizing their activity in the aqueous root's extracts. Another possibility is that active compounds from the roots were pres-

Only preliminary screening of phytochemicals was done on crude extracts. Isolation

of active pure compounds was only done on roots (3 compound identified) and not on leaves, even though leaves showed so much active compounds. This compound identification still needs to be done and testing of them has not been done either. Both leaves and roots extracts showed the presence of saponins. However, the identification and isolation of those specific saponins has not been done. Intensive work still needs to be performed regarding the mutagenicity or genotoxicity of the plant extracts for the confirmation of the safety of *Asparagus laricinus Burch.*, as the root cytotoxicity results were promising, while the safety of the leaves also needs to be investigated. The toxicological study of the roots of *Asparagus laricinus Burch.* confirmed that the plant extract did not cause any harm *in vivo* and can thus be considered as non-toxic. However, the *in vivo* anticancer activity of the root extract has not been done in order to confirm or corroborate the results obtained in the screening study that was conducted. Both *in vitro* and *in vivo* anticancer, cytotoxicity and mutagenicity studies still need to be done on the leaf extract. The ability of the crude extract of this plant as an antibacterial agent was confirmed, and findings supported the use of this plant against infections. However, not all ethnobotanical claims of this plant have been confirmed as the anti-TB activity, anti-inflammatory activity and its ability as a diuretic still needs to be elucidated.

**English:** Wild Asparagus climbing asparagus fern, bush asparagus;

ent and these were missed during the phytochemical screening of this plant. Mokgawa evaluated possible toxic effects of dried roots, stem and leaves of *Asparagus laricinus Burch.* extracts using Sprague Dawley rats as animal models [18]. Histological evaluation could not reveal any pathological changes in both aqueous and ethanoic extracts across all levels of dosages. Full blood count results could not point in the direction of toxicity, adverse effects or hazards as indicated by statistically similar results between the exposed and unexposed groups, using both aqueous and ethanol extracts at different concentrations [18]. According to results obtained by Mokgawa, histological assessment has proven that both aqueous and ethanolic extracts of *Asparagus laricinus Burch.* had no detrimental or adverse effects on vital organs of Sprague Dawley rats [18]. Tissue damage, lesions or inflammation were not observed on the kidney, liver or spleen of treatment groups in comparison to the control group. The pattern was observed across increasing doses of aqueous and ethanolic extracts. It was, therefore, concluded that toxicological evaluation of *Asparagus laricinus Burch.* extracts may be considered relatively free of toxicity when given orally, because it did not cause death, damage or inflammation to tissues, nor did it produce any remarkable biochemical and hematological adverse effects in both male and female Sprague Dawley rats [18]. Further studies may also be conducted to demonstrate *in vivo* efficacy against cancer as studies to date were done using cell lines *(in vitro* studies).

*DOI: http://dx.doi.org/10.5772/intechopen.87048*

**4.4 Reflections and future recommendations**

#### *Medicinal Properties of Selected Asparagus Species: A Review DOI: http://dx.doi.org/10.5772/intechopen.87048*

*Phytochemicals in Human Health*

ducted in the Unit of Drug discovery, CUT [18].

*Burch*., as demonstrated by Ntsoelinyane and Mashele [15].

acid; and as it is a known to protect cells from oxidative stress.

the *A. laricinus Burch.* aqueous extract [7].

result in antimicrobial medicines [16], anti-inflammatory drugs, anticancer drugs, and plant-based anti-oxidants. Phytochemical screening was performed on the leaves and roots of *Asparagus laricinus Burch.*, and parts had tannins, saponins, terpenes, and steroids. However, only roots showed the presence of alkaloids. It was also shown that flavonoids which are known to have an ability to inhibit microbial growth also scavenge antioxidants. The leaf extract contained steroids, these being important compounds as sex hormones. Both leaves and stem extracts showed that they contain saponins, which ultimately has a suppressive effect on inflammation [17]. This is a main reason why *Asparagus laricinus Burch.* is used in traditional medicine. *In vivo* anti-inflammatory activity studies of this plant are being con-

Tannins are generally found in most plant parts: bark, wood, leaves, fruits and roots, and can have a toxic effect on filamentous fungi, yeasts and bacteria [19]. No alkaloids were found in this study. Leaf extracts further showed positive antibacterial activity on *S. aureus*, *S. saprophyticus*, *E*. *cloacae* and *B. subtilis*. Inhibition of *Staphylococcus aureus* by the *Asparagus laricinus Burch.* plant extract demonstrates huge potential for using this plant to extraction in the treatment of microbial infections, especially in the light of the growing antibiotic resistance in micro-organisms. The presence of phenols correlates with the antibacterial and antioxidant activities of the leaf extract of *Asparagus laricinus* 

In recent times, there has been a growing interest in finding antioxidants which occur naturally to replace synthetic antioxidants, many of which are being restricted due to their carcinogenicity [20, 21]. Free radical scavenging molecules such as flavonoids, tannins, alkaloids, quinones, amines, vitamins and other metabolites have anti-inflammatory, anti-carcinogenic, antibacterial and antiviral activities [22]. *Asparagus laricinus Burch.* aqueous extracts of roots and leaves showed positive antioxidant activity with DPPH assay [15]. Flavonoids contain anion radicals and produce membrane bound enzymes [23]. This could be the reason for the mechanisms of antioxidative action of *Asparagus laricinus Burch.* leaf extract. The antioxidant that is found in the plant extract may also be due to polyphenols as phenolics being present [24]. The aqueous leaves extract of *Asparagus laricinus Burch.* produced significant activity as an antioxidant, and this could be due to the presence of ferulic

Using the Ames test on *Salmonella typhimurium* strains*:* TA97, TA98, TA100 and

The phytoconstituents detected from *Asparagus laricinus Burch.* may have caused the cytotoxic activity, although their precise mode of action is poorly understood. Only a few compounds were isolated from the roots of *Asparagus laricinus Burch.*: indole-3-carbinol, α-sitosterol and ferulic acid. β-Sitosterol have numerous therapeutic and chemo-preventive uses in the medical field [26, 27]. Prostate cancer is being treated by Indole-3-carbinol [28]. Anticancer activity on breast (MCF7), renal (TK10) and melanoma (UACC62) using roots aqueous and ethanol extracts was

TA102 without any metabolic activation, Mashele and Fuku [25] evaluated the mutagenic and antimutagenic properties of the aqueous root's extracts of this plant. The extract was non-mutagenic towards all strains, had moderate inhibitory effect on TA100, and had low inhibitory effects on TA102 and TA97 [7]. Root aqueous extract showed an indirect mutagenic effect toward TA102 after metabolic activation, but not in TA97, TA98 and TA100. However, it was found that the Ames test, without S9 (liver extract of a rat, hamster or human) metabolic activation, could only detect direct mutagens, while S9 metabolic activation allowed the detection of indirect mutagens which were mostly caused by conjugation reactions of metabolic oxidation systems. Cytotoxicity activity on Vero cells was also elucidated. The cytotoxicity tests indicated no cytotoxic effect below 500 μg/ml concentration of

**210**

shown by Mashele and Kolesnikova [29], who revealed that ethanol extracts were very active while aqueous extracts were weakly active. However, ethanol roots extract only showed the presence of tannins while the aqueous roots extract showed a number of active phytochemicals. These results should be investigated further to elucidate the aforementioned difference. It may be that the presence of other active compounds somehow affected the ability of tannins by neutralizing their activity in the aqueous root's extracts. Another possibility is that active compounds from the roots were present and these were missed during the phytochemical screening of this plant.

Mokgawa evaluated possible toxic effects of dried roots, stem and leaves of *Asparagus laricinus Burch.* extracts using Sprague Dawley rats as animal models [18]. Histological evaluation could not reveal any pathological changes in both aqueous and ethanoic extracts across all levels of dosages. Full blood count results could not point in the direction of toxicity, adverse effects or hazards as indicated by statistically similar results between the exposed and unexposed groups, using both aqueous and ethanol extracts at different concentrations [18]. According to results obtained by Mokgawa, histological assessment has proven that both aqueous and ethanolic extracts of *Asparagus laricinus Burch.* had no detrimental or adverse effects on vital organs of Sprague Dawley rats [18]. Tissue damage, lesions or inflammation were not observed on the kidney, liver or spleen of treatment groups in comparison to the control group. The pattern was observed across increasing doses of aqueous and ethanolic extracts. It was, therefore, concluded that toxicological evaluation of *Asparagus laricinus Burch.* extracts may be considered relatively free of toxicity when given orally, because it did not cause death, damage or inflammation to tissues, nor did it produce any remarkable biochemical and hematological adverse effects in both male and female Sprague Dawley rats [18]. Further studies may also be conducted to demonstrate *in vivo* efficacy against cancer as studies to date were done using cell lines *(in vitro* studies).
