Matrine is a traditional Chinese medicine and botanical pesticide with broad biological activities, including pharmacological and agricultural activities. In present work, two matrine derivatives have been successfully synthesized via introducing indole and cyclohexylamino to 13 position of matrine, respectively, with sophocarpine as starting material, and structurally characterized via infrared spectroscopy(IR), MS, 1 H NMR, 13 C NMR and X-ray crystal diffraction. The results of the in vitro biological activity tests showed that these two matrine derivatives exhibited even better activities against human cancer cells Hela229 and insect cell line Sf9 from Spodoptera frugiperda (J. E. Smith) than that of parent matrine, suggesting that the heterocyclic or cyclic group can dramatically increase the biological activity of matrine. It is worth to mention that 13-indole-matrine could possibly inhibit the growth of insect cells or human cancer cells by inducing cell apoptosis. The results of the present study provide useful information for further structural modifications of these compounds and for exploring new, potent anti-cancer agents and environment friendly pesticides.

Large-area electronics as switching elements are an ideal option for electrode-array-based digital microfluidics. With support of highly scalable thin-film semiconductor technology, high-resolution digital droplets (diameter around 100 μm) containing single-cell samples can be manipulated freely on a two-dimensional plane with programmable addressing logic. In addition, single-cell generation and manipulation as foundations for single-cell research demand ease of operation, multifunctionality, and accurate tools. In this work, we reported an active-matrix digital microfluidic platform for single-cell generation and manipulation. The active device contained 26,368 electrodes that could be independently addressed to perform parallel and simultaneous droplet generation and achieved single-cell manipulation. We demonstrate a high-resolution digital droplet generation with a droplet volume limit of 500 pL and show the continuous and stable movement of droplet-contained cells for over 1 h. Furthermore, the success rate of single droplet formation was higher than 98%, generating tens of single cells within 10 s. In addition, a pristine single-cell generation rate of 29% was achieved without further selection procedures, and the droplets containing single cells could then be tested for on-chip cell culturing. After 20 h of culturing, about 12.5% of the single cells showed cell proliferation.

BACKGROUNDMatrine is an important traditional plant‐derived insecticide with broad‐spectrum activity. However, due to its moderate activity, matrine is mainly applied in combination with other pesticides. In order to discover new potential natural‐product‐based crop protection agents, a series of matrine derivatives characterized by cyclohexylamine group were synthesized to screen their insecticidal activity against seven typically agricultural pests.RESULTSThe structural configurations of compounds were characterized by IR, 1H NMR, 13C NMR, MS and XRD, with the pure yields of 42%, 65% and 71%, respectively. Although all compounds showed poor insecticidal activity against five lepidoptera pests, the compounds 2 and 4 displayed remarkable insecticidal activities against Lipaphis erysimi and Mulberry Root‐Knot Nematode with a concentration‐dependent manner within 0.5~1.5 mg/ mL. Compared with matrine (60%), compounds 2 and 4 exhibited potent insecticidal activities against L. erysimi, with a corrected mortality of 83.3% and 89.7%, respectively. They also showed excellent control effects on Mulberry Root‐Knot Nematode, with corrected mortality as high as 88% and 80%, respectively.CONCLUSIONAll four synthesized matrine derivatives showed poor insecticidal activity against five lepidoptera pests, but the compounds 2 and 4 exhibited much stronger insecticidal activities against L. erysimi and Mulberry Root‐Knot Nematode than matrine. Combined with the structural characteristics of compounds 1~4, we conclude that 4‐methylcyclohexylamine, not the carbon disulfide group or cyclohexylamine group alone, mainly contributed to the improvement of insecticidal activities of matrine derivatives against these two agricultural pests. This work provides a direction and foundation for structural optimization of the matrine pesticides in the future. © 2020 Society of Chemical Industry

The invasion of Spodoptera frugiperda has imposed a serious impact on global food security. Matrine is a botanical pesticide with a broad spectrum of insecticidal activity which was recommended for controlling Spodoptera frugiperda. In order to discover effective insecticide for Spodoptera frugiperda, two matrine derivatives modified with carbon disulfide and nitrogen-containing groups were systhesized. And their inhibition activities on Sf9 cell were evaluated. The structural configuration of compounds were characterized by IR, HPLC, MS, NMR and XRD, with yields of 52% and 65%, respectively. The IC50 of the two newly synthesized compounds on Sf9 cell reduced to 0.648 mmol/L and 1.13 mmol/L, respectively, compared with that of matrine (5.330 mmol/L). In addition, microscopic observation of Sf9 cell treated with the compounds showed that the number of adherent cells decreased, the cells shrunk, vacuolated and apoptotic bodies appeared. The two newly synthesized compounds exhibited better inhibitory effect on Sf9 cell than that of the parent matrine, suggesting that the positive effect of the introduction of 1-pyrrolidinecarbodithioate and diethylcarbamodithioate groups to matrine. The morphological observation of Sf9 cell induced by derivatives indicated that apoptosis induction may be a mechanism that inhibits insect cell proliferation and exerts insecticidal effect.

C18H26ClN4O, orthorhombic, P212121 (no. 19), a = 5.3476(1) Å, b = 14.4068(2) Å, c = 22.3285(4) Å, V = 1720.23(5) Å3, Z = 4, Rgt(F) = 0.0328, wRref(F2) = 0.0774, T = 100 K.

C17H27N3OS2, monoclinic, P21 (no. 4), a = 8.8052(10) Å, b = 10.8860(10) Å, c = 18.6705(2) Å, β = 99.2730(10)°, V = 1766.24(3) Å3, Z = 4, Rgt(F) = 0.0298, wRref(F2) = 0.0802, T = 100.00(10) K.