User:LisaWeng/sandbox

== Rearrangement of Nimbin to Isonimbin == The mechanism involves H+ ion coordination with ethereal oxygen of the C-ring followed by cleavage to form a more stable allyl carbocation at the C-13 and deprotonation of H-17 to form a diene. Successive intramolecular attack of the H+ on the tertiary carbocation, leads to a 180o rotation of bond between C-8 & C-14 and ring closure to produce the rearranged product with cyclic ether: Isonimbin.

Protocole:
Nimbin was taken in a 100mL single necked round bottom flask fitted with guard tube, followed by 10mL of acetonitrile. The solution is cooled to 0oC and 0.5ml of concentrated sulfuric acid is slowly added with stirring. The reaction is left until the room temperature is reached and stirred once again for 6 hours.

The completion of the reaction was monitored by Thin-Layer Chromatography. After completion, the flask was immersed in ice-bath and aqueous ammonia was added slowly until the pH reaches 7-8, the solution was concentrated under reduced pressure using rotary evaporator and poured into ice-cold water and extracted using ethyl acetate and the crude product extract was purified using flash (under nitrogen) column chromatography and pure product eluted at 16% Ethyl acetate in hexane. (Isonimbin - Yield: 62%).

== Semi-synthetic modification nimbolide to 6-homodesacetylnimbin and 6-desacetylnimbin == Nimbolide has been isolated from the neem leaves and semi-synthetically modified to improve the bioefficacity of the compound.

With the induce of steric hindrance through transesterification of the alkyl group in the –COOMe moiety of nimbolide using Titanium isopropoxide and ethanol, a new product has been formed: 6-homodesacetylnimbin, that has been identified through spectroscopic and crystallographic methods. (IR band at 1712 cm-1 for the product and 1778 cm-1 for nimbolide, (product eluted at 26,31 min for the product and 20,76 min for nimbolide)

The cytotoxic property of 6-homodesacetylnimbin was determined and compared with nimbolide, 6-desacetylnimbin and nimbin:

Absence of any activity and very little activity presented by nimbin and 6-desacetylnimbin depicts that the lactone ring in nimbolide is very important for anticancer activity.

However, ED50 value for 6-homodesacetylnimbin illustrates moderate activity.

Thus, steric hindrance through the presence of a large group or a lactone ring over the C-28 position may be crucial to transmit cytotoxic activity.

== Anti-inflammatory with N1, N2 and N3 == An anti-inflammatory role has been demonstrated both in vitro and in vivo models using nonsteroidal tetranortriterpenoid, Nimbin (N1) and its analogs (N2 and N3).

They were able to improve wound healing by cell proliferation, and to reduce the Reactive oxygen species (A type of unstable molecule that contains oxygen and that easily reacts with other molecules in a cell).

For the experiences, all the reactions were produced with the commercially available starting materials without any further purifications. The molecule of Nimbin was isolated from raw neem seed.

In-vitro: anti-inflammatory activity by membrane stabilizing

The effects of Nimbin were tested on hemolysis of human red blood cells induced by heat and hypotonicity.

In-vivo: Estimation of ROS levels in zebrafish larvae via inflammation

To detect intracellular Reactive oxygen species generation by induced inflammation in zebrafish, an oxidation-sensitive fluorescent DCF-DA sample was used. The larvae were treated with N1, N2 and N3.