Abstract
This study was aimed at comparing the essential oils obtained from Heteromorpha arborescens leaves by Solvent-Free Microwave Extraction (SFME) and Hydrodistillation (HD) methods in terms of their chemical compositions, yield, CO2 emission, and energy consumption. The solvent-free microwave extraction method indicated a higher oil yield of 0.7 mL/200 g (0.35%) as compared to 0.59 mL/200 g (0.295%) obtained through hydrodistillation. GC-MS analysis of the oils revealed a total of 52 chemical components from both methods with the presence of 35 (96.52%) and 30 (71.15%) chemical constituents for HD and SFME, respectively. The major constituents observed in the essential oil extracted by SFME methods include α-pinene (6%), D-limonene (11.27%), β-ocimene (9.09%), β-phellandrene (6.33%), β-mycene (8.49%), caryophyllene (5.96%), and camphene (4.28%). However, in the hydrodistillation method, the oil was majorly composed of a-pinene (4.41%), β-pinene (10.68%), β-ocimene (6.30%), germacrene-D (5.09%), humulene (5.55%), and α-elemene (6.18%). The SFME method was better in terms of saving energy (0.25 kWh against 4.2 kWh of energy consumed), reduced CO2 emission (200 g against 3360 g of CO2), a higher yield, and better quality of essential oil due to the presence of higher valuable oxygenated compounds (8.52%) against that of the hydrodistillation method (2.96%). The SFME method is, therefore, a good alternative for extracting the oils of H. arborescens leaves since the essential oil yield is higher with more oxygenated compounds, considerable energy savings, lower cost, and reduced environmental burden at substantially reduced extraction time (30 min as opposed to 180 min).
Highlights
Plants have a long history of therapeutic use in the management of diseases since time immemorial
A total of 52 compounds obtained by hydrodistillation and solvent-free microwave extraction methods are summarized in Table 1. irty-five compounds representing 96.52% of the total essential oil present were obtained in the hydrodistillation method
solvent-free microwave extraction (SFME) and Microwave Hydrodiffusion and Gravity (MHG) methods are two new green techniques employed in the extraction of quality essential oils at a lower cost, reduced time, and environmental footprints [23]
Summary
Plants have a long history of therapeutic use in the management of diseases since time immemorial. Complex, and aromatic volatile compounds produced by plants, and they are generally present at low concentrations. Schltdl (Apiaceae) can be referred to as a large shrub, small or medium deciduous tree [5]. It is regarded as an important medicinal plant throughout its distribution area in tropical Africa and has been used for the treatment of many ailments including helminthiasis [6], abdominal pains, infertility, nervous disorders, and tuberculosis [5]. The volatile oil of H. arborescens leaves is known to contain sabinene, δ-3-carene, myrcene, germacrene-D, limonene, (Z)-β-ocimene, β-phellandrene, and α-pinene as major constituents, and it possesses both antibacterial and antifungal activities [5]. The essential oil of H. arborescensis is vital in the development of new pharmaceutical and health products in Southern Africa for headache, inhalant, and aromatherapy [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
