**3. Secondary metabolites from plant tissue culture**

Overharvesting of medicinal plants for their secondary metabolites may lead to their disappearance from the natural habitats. Due to this, researchers turn to alternative and innovative methods to meet the increased demand for these natural products. In particular, plant tissue culture has become a well-established and attractive alternative for mass production of secondary metabolites through callus, suspension, and organ culture [18, 19]. Tissue culture itself is defined as the technique of maintaining plant tissue in vitro in a synthetic medium under controlled conditions, and it is reported to be extremely useful for commercial production of therapeutically important compounds [20].

There are many advantages of using plant tissue culture for producing metabolites including the (i) ability to improve the production of certain compounds within the plant cell using elicitors and plant hormones to manipulate the cultured cells [21], (ii) the ability to continuously produce secondary metabolites through propagation in sterile bioreactors independently of growth conditions such as soil content and microclimate [22], (iii) the ability of in vitro plant tissue culture to achieve higher rates of metabolism than the in vivo differentiated intact cells [22], and (iv) the ability to bypass the structural complexity of the plant organism rendering it to be a convenient tool in research studies [23].

The current evaluation of secondary metabolite compounds in various culture types of medicinal plants available in Malaysia is summarized in **Table 2**. Most of these studies involved with the cell suspension culture compared to other types of plant culture that are also frequently used for secondary metabolite production such as hairy roots and shoot culture.

(9-methoxycanthin-6-one)

9-methoxycanthin-6-one)

Cell suspension Flavonoids Cardiovascular diseases

Cell suspension Phenolics (anthraquinones) Antiviral, antimicrobial,

Cell suspension Terpene (patchouli alcohol) Nausea, diarrhea, and

Cell suspension Phenolics Antioxidant [32]

Alkaloid (9-hydroxycanthin-6-one and

**Secondary metabolites Biological activities Reference**

Secondary Metabolite Research in Malaysia: Current Status and Future Prospects

antidiabetic

Phenolics Antioxidant [30]

activities

headache

Cytotoxicity activity against human breast cancer (MCF-7) and human lung cancer (A-549) cell lines

http://dx.doi.org/10.5772/intechopen.76305

and postpartum treatments,

cytotoxic, and antitumorpromoting and antioxidant [27]

105

[28]

[29]

[31]

[33]

The dengue prevalence in Malaysia remains overwhelming, with increasing rate of incidence reported annually. According to the latest WHO report, in 2016, more than 375,000 suspected cases of dengue were recorded in the Western Pacific Region, 100,028 of which occurred in Malaysia [34]. The steady surge of cases over the years has prompted serious efforts from the government and the community, including intensive efforts in both vector control and elucidation of potential therapeutic agents. Although evaluation of several vaccines is currently in progress, the ambivalence of such treatment with regard to serotype

**4. Case study: secondary metabolites in the prevention and** 

**treatment of dengue**

**Plant species Type of plant** 

*Eurycoma longifolia* **Jack (Tongkat Ali)**

*Ficus deltoidea* **Jack (Mas Cotek)**

*Justicia gendarussa* **(Gandarusa)**

*Morinda elliptica* **(Mengkudu)**

*Orthosiphon stamineus* **(Misai kucing***)*

**(Nilam)**

*Pogostemon cablin*

**culture**

Cell suspension culture

Callus, cell suspension

Research conducted in various institutions in Malaysia.

**Table 2.** Different types of plant tissue culture and their secondary metabolites.

Hairy roots Alkaloid

**4.1. Dengue fever**



**Table 2.** Different types of plant tissue culture and their secondary metabolites.

The current evaluation of secondary metabolite compounds in various culture types of medicinal plants available in Malaysia is summarized in **Table 2**. Most of these studies involved with the cell suspension culture compared to other types of plant culture that are also frequently used for secondary metabolite production such as hairy roots and shoot culture.
