Substitution of aldehyde group at C-3 position of indole led to significant reduction in the activity. In separate study published in 2019, Li and colleagues43 synthesized two series consisting of 22 novel indole-vinyl sulfone derivatives and tested them for tubulin inhibitory efficacy. They came up with new 3-aryl-thio and 3-aroyl-1H-indole derivatives with a heterocyclic ring at position 5, 6, or 7 of the indole moieties. The cis structure has been demonstrated to be significant for anticancer action through binding to the CBS. A vast data available in the literature mentioned various FDA approved indole drugs effective against various kinds of cancers. From overall results, 61a turned out to be an interesting derivative which may help to synthesise a new library of derivatives124. Derivative 61c (Fig. 12) was able to inhibit the cell proliferation in SUIT-2 and CAPAN-1 cells having IC50 value of 11.8 and 10.49 μmol/L respectively. In studies culturing human vascular endothelial cells (HUVEC), it has been shown that 2-methoxy estradiol is a primary regulator of cell growth and apoptosis. In case control studies, higher levels of circulating estrogen predict the degree of prostate enlargement. Recent work shows that estradiol, the active form of estrogen, provokes increases in prostate specific antigen (PSA) production in human prostate tissue. In one of the studies, androgen-dependent prostate cancer cells treated with DIM grew 70% less than androgen-dependent untreated cells. Research shows that a chemical derived from cruciferous vegetables like broccoli could be effective against the growth of prostate cancer cells. To determine whether men are at risk for prostate cancer, they are usually tested for levels of prostate-specific antigen (PSA), a growth factor for prostate cancer. DIM also inhibited dihydrotestosterone (DHT) stimulation of DNA synthesis in the androgen-dependent cancer cells. Diindolylmethane (DIM), a stable indole, has been reported to enhance insulin sensitivity and encourage abdominal fat loss. Diindolylmethane (DIM) is a stable indole found in cruciferous vegetables Interestingly, "among SLE patients the aromatase activity varied inversely with the disease activity. Also keep in mind that if testosterone production is turned on high, the body may not produce enough DHEA to meet this new found demand. DIM (diindolylmethane) encourages the conversion of estrogens to safer forms and helps reduce elevated levels. These events, however, are nullified by 2-hydroxy, which doesn’t provide the negative feedback message to the pituitary induced by estrogen. The 2-hydroxy estrogens promoted by usage also increase testosterone synthesis through another mechanism. Thus, these plasma binding proteins instead latch on to 2-hydroxy, leaving greater levels of free testosterone, including that produced through the use of supplemental prohormones. The mechanism behind this is that 2-hydroxy estrogens have a greater binding affinity for the blood proteins that "lock up" testosterone in the blood. More importantly from an anabolic point of view, the level of free testosterone rises in the blood with use of diindolylmethane. The indole moiety is also called bioisosteres as it has physical and chemical properties akin to other biological molecules. The NH group of indole has a key role in interacting with the target bioreceptor, whereas the synthesized benzofuran and benzothiophene derivatives show mild-to-moderate affinity toward the targeted bioreceptor . The hydrophobicity of indole moieties is almost equal to the phenyl ring and less than the classical isosteric benzofuran and the benzothiophene group. This indole moiety is capable of forming H-bonds via pi-pi stacking, NH moiety, or cation-pi interactions, through the aromatic moieties . Aromatase inhibitors like DIM (diindolylmethane), Indole 3 carbinol, and chrysin should be avoided, as they will enhance any preexisting androgen / estrogen dominance. There is research to support that DIM increases conversion of some estrogen hormones into their estrogen metabolites. I have not found any research to support DIM inhibiting Aromatase activity, in fact in may increase Aromatase activity. The testosterone level has an inverse relation to activity in the open-field test. Before administration and 1 year after administration, serum testosterone level was measured, and the International Prostate Symptom Score and a urodynamic study were used to assess subjective and objective symptoms. But still new research is required to get better understanding about the origin of cancer and drug resistance in cancer patients along with advancement in multi-drug therapy by indole-based molecules can be expected in the near future. Considerable researches in this area are evidenced by the facts that numbers of indole-based molecules are approved recently or are in pre-clinical and clinical stages. The research in the field of apoptosis has extended to incorporate research in about all areas of cell biology from cancer to cardiovascular diseases. In 2018, N-substituted indole-3-carboxylates were prepared in good yields with the help of t-BuOK/DMF system under transition metal free conditions reported by Bugaenko and others16. Also, in this reaction, PISA acts both as Brønsted acid and oxidizing agent whereas, water improves the efficacy of the reaction by acting as a catalyst (Fig. 1). The avoiding hazardous oxidant, high boiling point solvents such as DMF and DMSO and heavy-metal cocatalysts were some of the benefits of this method which can be applied to other pharmaceutical synthesis (Fig. 1).
