Foods 9(8), 1136 (2020). TLC of methanolic decoctions and ultrasonication extracts from Zingiber officinale (Zingiberaceae) rhizomes, as well as from commercial ginger formulations, on reverse-phase C18-silica gel with ethanol – water 13:7. Densitometry at 200 nm in absorbance and reflectance modes for 6-shogaol (SHO, hRF 36) and 6-gingerol (GIN, hRF 53). Standards of these vanilloid phenolics were also used for calibration; linearity was in the range of 100–700 ng for SHO and of 50–600 ng/band for GIN; interday and intra-day precisions were below 1.6 %. The LOD and LOQ was 34 and 101 ng for SHO, 17 and 51 ng for GIN, respectively. Recovery rates were 98.8–101.6 % for SHO and 99.0–101.5 % for GIN. For each extract, SHO and GIN levels were calculated, the yields after ultrasonication extraction were 10-25 % higher than with the corresponding decoctions. Comparison with other published methods (LC-MS and HPLC) showed superiority of this new method in terms of linearity range, accuracy and precision.

3 Biotech 10(8), 344 (2020). Rauvolfia serpentina (Apocynaceae) was cultivated in vitro as leaf-derived callus and as plantlet cultures obtained from tissues of nodal explants, without or with cadmium chloride as elicitor of alkaloid production. TLC of methanol – ammonia 10:1 extracts of callus and plantlet organs (leaves, stems and roots) on silica gel, along with indole alkaloids reserpine and ajmalicine in different concentrations. Development with chloroform – toluene – ethyl acetate – diethyl amine 7:7:4:1. Detection under UV light and by densitometry scanning in absorbance mode at 240 nm and 280 nm. The highest alkaloid yields were obtained for reserpine (hRF 15) in roots (191µg/g) and for ajmalicine (hRF 45) in callus (131µg/ml) when culture had been done with elicitor 0.15 mM for 6 days and 4 days, respectively (at 0.20 mM, an inhibiting effect was observed).

Heliyon 6(8), e04654 (2020). HPTLC of ethanolic extracts of three algae (100µg/band) on silica gel, along with carotenoid standards (10µg/band), developed with toluene – acetone 7:3. Detection under white light. Carotenoids appeared orange or yellow, chlorophylls green, pheophytins dark khaki. Carotenoid patterns of the algae were very different depending on the family: red alga Eucheuma denticulatum (Solieriaceae) contained mainly zeaxanthin and lutein (hRF 44) and β-carotene (hRF 88), but also β-cryptoxanthin (hRF 69-71) and fucoxanthin (hRF 39); brown alga Sargassum polycystum (Sargassaceae) contained mainly fucoxanthin, and also cryptoxanthin; green alga Caulerpa lentillifera (Caulerpaceae) contained mainly zeaxanthin, but also astaxanthin (hRF 61) and canthaxanthin (hRF 77) in smaller amounts. Separately, HPLC-MS was used to confirm and quantify these compounds, which was necessary for carotenoids with similar hRF values: zeaxanthin and lutein (hRF 44), and β-carotene and lycopene (hRF 88).

Heliyon 6(7), e04481 (2020). TLC of two successive stem-bark macerates (dichloromethane – methanol 1:1 and 0:1) of Kigelia africana (Bignonaceae) on unmodified silica gel, developed with dichloromethane – ethanol 19:1. Detection by spraying with stannic chloride (tin IV chloride) in chloroform – acetic acid – water 8:8:1 and heating at 100°C for 10 min. Visualization under UV showed terpenoids, phenols, steroids and flavonoids as indigo zones. The two extracts provided similar profiles but with different intensities.

J Pharm Bioallied Sci. 12(2), 139-145 (2020). An HPTLC method was validated for the fingerprint of flavonoids and other phenolic compounds (rutin, apigenin, luteolin, caffeic acid, chlorogenic acid, rosmarinic acid) in methanol macerates of dried aerial parts of five Lamiaceae (subfamily Nepetoideae: Dracocephalum moldavica, Lophanthus anisatus, Monarda fistulosa, Ocimum americanum, Satureja hortensis). HPTLC of extracts and standards on silica gel with chloroform – ethyl acetate – formic acid 5:4:1 or with ethyl acetate – formic acid – water 15:1:1. Detection under UV light before and after spraying with aluminium chloride 1 % in methanol. Rosmarinic acid was present and abundant in all extracts and was also quantified by densitometry at UV 366 nm without derivatization. The LOD was 29.2 µg/mL; the rosmarinic acid concentration range was between 12.6 mg/g (Lophanthus) and 24.8 mg/g (Dracocephalum).

J. Planar Chromatogr. 33, 547-565 (2020). HPTLC of seven species of the genus Justicia (J. adhatoda, J. beddomei, J. betonica, J. carnea, J. gendarussa, J. santapaui, J. wynaadensis) on silica gel with toluene - ethyl acetate 9:1 for n-hexane extracts and toluene - ethyl acetate 4:1 for chloroform extracts and toluene - ethyl acetate - methanol 7:3:1 for methanol extracts. Detection by spraying with anisaldehyde - sulfuric acid reagent, followed by heating at 105 °C for 5 min. Densitometric scanning at 254 nm, 366 nm and 550 nm.

J. Planar Chromatogr. 33, 631-646 (2020). HPTLC of azilsartan medoxomil (1) and chlorthalidone (2) on silica gel with toluene - methanol - ethyl acetate - formic acid 35:10:5:1. Quantitative determination by absorbance measurement at 241 nm. The hRF values for (1) and (2) were 55 and 36. Linearity was between 800 and 4000 ng/zone for (1) and 250 and 1250 ng/zone for (2), respectively. Intermediate precision was below 2 % (n=3). The LOD and LOQ were 15 and 44 ng/zone for (1) and 10 and 32 ng/zone for (2). Recovery was between 100.8 and 101.7 % for (1) and 99.4 and 101.0 % for (2).

J. of Chromatogr. Sci. 59 (6), 576-583 (2021). HPTLC of simeprevir (SMV) and sofosbuvir (SOF) on silica gel with ethyl acetate – hexane - methanol 5:4:1. The hRF of SMV was 67 and of SOF 43. Quantitative determination by densitometry at 273 nm. The linearity range was between 60-1000 ng/band for SMV and 70-1200 ng/band for SOF, with good correlation coefficients (0.9993-0.9997) for both.  LOD was 15 and 22 ng/band and LOQ 44 and 66 ng/ band for SMV and SOF, respectively.