Planta Med. 85(2), 154-159 (2019). Two new cycloartane triterpene heterosides (cimiheraclein F and a shengmanol derivative) isolated from Actaea heracleifolia aerial parts (Ranunculaceae) were submitted to acid hydrolysis (HCl 0.4 M in methanol 60 %, 90°C, 2 h). The glycone moieties were purified and developed on TLC silica gel with ethyl acetate – chloroform – methanol – water 3:2:2:1. Detection after spraying with sulfuric acid 10 % in water and heating. The glycones were identified in both cases as L-arabinopyranose by comparison of the RF values (and of specific optical rotation) to a standard.

Planta Med. 85(2), 112-117 (2019). A fraction of an ethanolic extract of Dolichos trilobus roots (Fabaceae) was eluted on a silica gel column with different mixtures of petroleum ether and acetone. This fractionation was monitored by TLC on silica gel (eluent not given), derivatization by spraying with sulfuric acid 10 % (in ethanol) and heating (100 °C). Further isolation steps allowed the identification of eight coumestans in two subfractions: dolichosins A–D, isosojagol, phaseol, psoralidin, dehydroisopsoralidin.

Sci. World J. 2020, 7367836 (2020). TLC of ethyl acetate fractions of hydro ethanolic extracts obtained from Cassia siamea leaves (Caesalpiniaceae) on silica gel with chloroform – ethanol 17:3, as well as cassiarin A (an isoquinoline alkaloid, hRF 34) as standard. Visualization under UV light. Densitometry scanning at 368 nm for cassiarin A. Linearity was in the range of 400–1400 ng; intra-day precision was below 4 %; LOD and LOQ values were 3 and 8 ng, respectively; recovery rates were 102.8–120.1 %. The cassiarin A concentrations in the samples (given as w/v, the volumes being those of the first undried hydro-ethanolic extracts) varied depending on the origin (ground and climate) of the leaves.

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).