I would suggest to consider supercritical CO2 for this; could someone who really works with it post any comments from practical point of view ?

Dear Ashvin

Before, I suggest you a correct distillation apparatus/ procedure for oil extraction. One of the foremost question arises here is the quantity of plant material i.e., Ocimum. If you are working on lab scale level, then certainly you should go for  Clevenger-type apparatus (hydro-distillation based apparatus), a commonly used glass based device popular among researchers throughout the World including India.

There are also microwave based distillation units available.

You may also try supercritical CO2 extraction as rightly mentioned by Dr Vladimir in his answer, if the unit is available near to you. Supercritical CO2 based distillation is quite convincing and time saving  technique available till date.

Furthermore, for larger qualities such as 50/ 100 kg or more materials, steam based distillation shall be appropriate.

Good Luck

you can use destillation for The extraction of oil from plants, its the most using methode

Thank you Thamere cheriet, chandan and Vladimir  sir

Hydro-distillation using Clevenger apparatus is the easiest method for essential oil isolation in lab scale. 

Similar questions have been asked in RG before, Check these links

https://www.researchgate.net/post/Is_anyone_working_on_new_techniques_of_distilling_aromatic_plants_to_produce_essential_oils

https://www.researchgate.net/post/Did_anyone_analyse_the_essential_oil_components_present_in_the_vapors_escaping_from_Clevenger_hydro-distillation_condenser_vent

https://www.researchgate.net/post/What_are_the_effects_of_distillation_water_pH_on_the_yield_recovery_and_chemical_composition_of_an_essential_oil2

https://www.researchgate.net/post/What_are_the_techniques_used_for_the_extraction_of_essential_oils_from_a_plant

https://www.researchgate.net/post/What_extraction_procedure_is_best_for_the_analysis_of_the_essential_oils_from_plants?_tpcectx=topic_detail&_trid=55d9ea255f7f719d138b4584_11

https://www.researchgate.net/post/How_can_we_prevent_froathing_during_extraction_of_essential_oils_by_hydrodistillation_using_clevenger_type_apparatus?_tpcectx=topic_detail&_trid=55d9ea255f7f719d138b4584_19

https://www.researchgate.net/post/How_do_I_extract_essential_oil_from_fresh_leaves_in_a_short_time?_tpcectx=topic_detail&_trid=55d9ea8e60614bc20f8b45e8_25

https://www.researchgate.net/post/How_to_extract_essential_oils_from_Clerodendron_inerme_leaves?_trid=55d9ea8e60614bc20f8b45e8_

https://www.researchgate.net/post/Can_we_do_essential_oil_distillation_by_solvent_instead_of_water?_trid=55d9ea8e60614bc20f8b45e8_

https://www.researchgate.net/post/How_much_water_do_we_need_for_micro-clevenger?_trid=55d9ea8e60614bc20f8b45e8_

Here is another similar thread

http://www.researchgate.net/post/What_is_the_best_method_for_essential_oil_isolation_What_is_difference_of_hydrodistillation_clevenger_apparatus_and_steam_distillation

1- distillation water (by clevenger).

2. Soxhlet methods.

You can use either:

Unfortunately you present no information on how the essential oil is stored in the plant organ and whch plant organ it i really is. That would make the answer more simple. Methods are:

1. Hydrodistillation. Most used method, but because it works with heat and water, it can generate artifcts (see liiterature).

2. Extaction of the plant material (dried or fresh) with petrol. The extract, however, will contain most lipophilic constituents in aditin to the essential oil constituents.

3. CO2 extraction. This owever needs a special equipment, but will be the most modern and specific one.

4. When the essential oil is contained in surface located essential oil cells (e.g. as for the Lamiaceae) you may also spoil the surface with petrol until theoil is separated from the leaves. (this is a very special method but will give you the native essential oil).

Hydrodistillation is the best one for Tulsi leaves. Though it will take time, but it is worth. 

Other high end methods can be tried as discussed in the thread already. 

Dear Ashvin,

Supercritical Fluid extraction has many advantages over other traditional methods, since you can control temperature and pressure, thus the density and affinity of your dissolvent over your compounds. Besides, allowing to conserve bioactivity of your desired molecules.

Perhaps the review in the link can be of your interest and help,

Bests,

http://onlinelibrary.wiley.com/doi/10.1111/1541-4337.12005/abstract

Thank you Gilda Joana Gil Chavez. very useful research work dear.

Steam distillation is the best. Although it will take time, but it is worth it.

Other upscale methods can be considered as already discussed in the thread.

Supercritical fluid extraction has many advantages compared to other traditional methods, since you can control (T, P) also making it possible to maintain the bioactivity of your desired molecules

What are the advantages of clevenger distillation method for essential oil extraction