**3. Effect of cultivation**

Effective systemic cultivation of essential oil producing plants is vital for the constant production of essential oil. Many factors influence the production of essential oil producing plants and may thus affect the production of the oils themselves [46]. Improved cultivars are now seen to give better quality and quantity of oil [5].

#### **3.1 Chemical composition**

Cultivation site as well as duration of cultivation has been said to affect the chemical composition of the essential oil of ginger, as well as their profile/constituents. The geographical location of the world in which ginger is cultivated also affects its chemical composition [47]. For instance, ginger grown in China was found with 43 different compounds [48] while the same species of ginger grown in Ghaziabad (India) possessed *Essential Oil of Ginger: Effect of Cultivation and Uses DOI: http://dx.doi.org/10.5772/intechopen.106682*

80 compounds with varied proportions reported [49]. At Fiji, the compounds present in the same species of ginger were varied from that in India [47]. This variation in chemical composition has affected the therapeutic and commercial use of ginger essential oil [5]. An instance would be the reported proportion of zingiberene which was found to be varied depending on the country of cultivation. 9.5% was found in ginger cultivated in Mauritius while 29.0% was found in Nigerian ginger, 1.3% in Sri Lankan ginger, 38.12% in Chinese ginger, 20–28% in Australian ginger, 46.2% in Indian ginger and so on [4]. The variation in the chemical composition of 17 cultivars of ginger from North India has also been documented (**Table 1**) [58].

### **3.2 Bioactivity**

Since the chemical composition of essential oil is seen to be affected by place and/ or duration of cultivation, it may be proposed that the cultivation also affects the bioactivity of the essential oil of ginger [5]. It is expected that since cultivation alters the chemical composition and peak of the different compounds present in ginger, the activity of a specific volatile oil of ginger will be dependent on the compounds present in the oil, its quantity as well as the intensity or peak of the compounds. For instance, sesquiterpenes which are known to be effective antioxidant and anti-inflammatory agents [59] are not abundant in Sri Lankan ginger essential oil while monoterpenes which are strong antimicrobial agents [60] are abundant in it [47].

### **3.3 Potency**


The peak intensity of ginger essential oil cultivated in different areas was considered and it was found that both the site and duration of cultivation affected the quality

#### **Table 1.**

*Effect of region of cultivation on ginger essential oil.*

or potency of compounds present in the essential oil [47]. The variation in the degree of pharmacological activity of the essential oil of ginger from different cultivars has been documented. It was noted that the intensity of the different compounds in different cultivars affects the potency of ginger essential oil. Essential oil of ginger from Brazil, for instance, was found to be more effective against *Staphylococcus aureus* bacteria compared with ginger essential oil from Veitnam. This has been attributed to variation in quantity of ar-curcumene, α-zingiberene, geranial, α-farnesene, β-bisabolene and β-sesquiphellandrene in both cultivars (**Table 1**) [7].

#### **3.4 Aroma and commercial use**

Australian ginger essential oil has a "lemony" odour due to the presence of high quantity (about 51–71%) of citral (neral and geranial). Jamaican cultivar contains higher levels of sesquiterpenes and lower citral content than the Australian cultivar. This is responsible for the intensity of aroma and pungency detected in the ginger oil with higher proportions of gingerols and other pungent compounds, thereby probably making it more commercially viable than those with less aroma (**Table 1**) [61].

#### **3.5 Weight yield**

The weight yield of ginger essential oil is also affected by cultivation. Kiran et al. [58] reported that the period of cultivation affected the weight yield of essential oil. In that study, it was found that ginger grown for only 5 months produced more essential oil than those grown for 7–8 months. This study was carried out in Sri Lanka and it is proposed that the higher essential oil yield in the less mature ginger is due to less fibre content and lower chemical intensity of the rhizome [58]. The variation in the quantity of essential oils produced from 17 cultivars of ginger from North India has been documented [58]. Indeed, different cultivars of ginger have been said to possess varied oil yielding capacities. This was reiterated by [5] who reported a difference in the proportion of ginger essential oil from different cultivars. In other studies, ginger grown in China was reported to give a 4.07% yield of the total weight of ginger [48] while that grown in India (Ghaziabad) yielded 1.26% of total weight of ginger. This disparity in quantity has affected the commercial availability of ginger essential oil significantly (**Table 1**) [5].

#### **3.6 Colour**

It has been reported that ginger essential oil derived from different geographical regions of the world differ in colour. Essential oil of ginger from West Africa is pale yellow, from India, it is yellow while that from China is pale yellow to amber. This might also affect acceptability and hence its commercial use. The colour variation has been attributed to alterations in the chemical composition of the oil from one region to another (**Table 1**) [7, 48].
