Effect of photoperiod and plant growth regulators on in vitro mass bulblet proliferation of Narcissus tazzeta L. (Amaryllidaceae), a potential source of galantamine

Abstract

Narcissus tazetta L., a bulbous plant belongs to the Amaryllidaceae family, contains alkaloid galantamine (GAL) with acetylcholinesterase inhibitory activity which has been recently considered to treat Alzheimer's disease (AD). In the current work, the effect of photoperiod (16/8 h light/dark and 24 h dark) and various concentrations of NAA, BAP, and GA₃ (0, 0.5, 1 and 2 mg l^‒1) on the in vitro mass bulblet regeneration of N. tazetta was studied. The GAL production ability of the regenerated bulblets was assessed by HPLC-UV-MS. Light treatments significantly affected the number of bulblet and leaf, the ratio of bulblet/leaf, and leaf length. The maximum number of bulblet (31.0 ± 1.58) and leaf (13.3 ± 1.33) was recorded from the cultures fortified with NAA and BAP (2 mg l^‒1) kept in 16/8 h light/dark, while the maximum leaf length (2.1 ± 0.92 cm) was measured on the MS medium containing 0.5 mg l^‒1 NAA and 2 mg l^‒1 BAP incubated in the same photoperiod. The average ratio of bulblet proliferation per explant was significantly different between studied photoperiod (1.1 ± 0.86) and 24 h dark (0.62 ± 0.31). The regenerated bulblets contained 40 and 20 µg g^‒1 DW GAL underexposed photoperiod and 24 h dark, respectively. This information could be useful in the commercial production of GAL as a valuable anti-AD compound through in vitro mass bulblet proliferation of N. tazetta.

Keywords: Amaryllidaceae ‧ In vitro culture ‧ Propagation ‧ Alkaloid ‧ Galantamine ‧ Alzheimer's disease.

Fig. 1

In vitro bulblet proliferation of Narcissus tazetta L. Map of collection site of the plant material studied (A), The plant used as explants source (B), The fresh and healthy bulbs (C), washed and sterile bulb used for explants excision (D), Sterile two-scale explants (E), established culture (F), proliferated bulblets on the MS medium containing NAA and BAP (2 mg l^‒1) kept in 16/8 h light/dark (G)

Fig. 2

The effect of photoperiod and plant growth regulators on the average number of bulblet (A) and shoot (B) proliferated from two-scale explants of Narcissus tazetta. Different letters showed significant differences among treatments at the level (P < 0.05). For a detailed description of treatment code cf. Table 2

Fig. 3

The effect of photoperiod and plant growth regulators on the ratio of bulblet (A) and shoot (B) proliferated from two-scale explants of Narcissus tazetta. Different letters showed significant differences among treatments at the level (P < 0.05). For a detailed description of treatment code cf. Table 2

Fig. 4

HPLC-UV-MS profiling of the methanolic extract of the regenerated bulblets of Narcissus tazetta L. HPLC-UV chromatogram recorded at 288 nm (A), corresponding total ion current chromatogram (TIC) (B), mass spectrum ([M+H]⁺) related to the of lycorine (C), and and mass spectrum ([M+H]⁺) related to galantamine (D)