The unavailable of approved clinical drug makes the finding of a potent compound against EV71 really important.
\(3{\rm C}^{{\rm pro}}\) is an essential protein for EV71 life cycle and infection, moreover, it has strict subtract and does not have a lot of homologues in mammalian cells [
35]. Thus, it is an excellent and attractive target for development of potent drugs. In this review, we summarized several classes of compound recently screened and also rupintrivir which is the drug of reference against
\(3{\rm C}^{{\rm pro}}\). Actually, rupintrivir and analogues are considered as the most potent
\(3{\rm C}^{{\rm pro}}\) inhibitors. However, NK-1.8k has almost the same potency and efficiency as rupintrivir (Table
1), and as more stable, it can take the place of rupintrivir as archetype of
\(3{\rm C}^{{\rm pro}}\) inhibitors. In fact, peptidomimetic compounds represent the most potent class with the minimal effective concentration (180 nM to 2.89 μM, Table
1). It might be due to the fact that they are synthetically designed to fit in the
\(3{\rm C}^{{\rm pro}}\) active pocket. Nevertheless, flavonoids class, which is composed of active compounds from plants, has satisfactory antiviral activity as well. Indeed, nowadays, the trend of using bioactive compounds as drug candidates is done more and more, because of their broad biological and pharmacological activities, their availability and safety towards the host cells. Besides, the screening of non-peptidyl compound has been tempted but only DC07090 among 50 other compounds has given a satisfactory result [
43]. Peptidomimetic compounds might be more potent and interesting than non-peptidyl-compounds. Hence, deep investigation, mainly in an appropriate animal model, should be done for luteoloside, quercentin and CPI which could be approved as EV71 therapy; while more and more peptidomimetic compounds should be designed and/or improved by using the revelation of
\(3{\rm C}^{{\rm pro}}\) structure as reference. Following the drug screening work, the 69th residue of
\(3{\rm C}^{{\rm pro}}\), which plays important role in conferring EV71 resistance, could be investigated in order to make sure that the virus will not develop a resistance mutation toward the potent drug as investigated by Wang et al. [
24]. Finally, the last recent strategy is the use of RNAi. In fact, there are few investigation about siRNA as therapy against EV71 infection; however, it has been successful against a wide range of viruses: Human immunodeficiency virus, hepatitis B/C virus, Influenza virus [
50‐
53]. Therefore, even if it is a challenging technique, investigating this strategy is worth it.
Table 1
Detailed list and classification of 3Cpro inhibitors: chemical structure, classes, effectivity, test in cell lines and animal models