Table 1. The top ten co-cited keywords with highest centrality.

Rank	Key words (1987–2018)	Counts	Centrality	Key words (2019–2022)	Counts	Centrality
1	Apocynum venetum l.	75	0.49	Antioxidant activity	4	0.77
2	Component	10	0.28	Acid	5	0.58
3	Hepatoprotective activity	3	0.27	Constituent	7	0.56
4	Identification	9	0.25	Apocynum venetum leaves	20	0.50
5	Antioxidant	6	0.23	Structural characterization	2	0.46
6	Apocynum venetum leaf extract	22	0.20	Oxidative stress	6	0.45
7	Mass spectrometry	2	0.20	Identification	9	0.30
8	Apocynum venetum leaves	37	0.18	Apocynum venetum l.	43	0.29
9	Apoptosis	3	0.18	Apocynum venetum fiber	10	0.28
10	Antioxidant activity	4	0.17	Apocynum pictum schrenk	3	0.27