Yes, LEDs can work on AC voltage. You can see the below example:
Frequency depends on your desired blinking frequeny that human naked eyes are able to capture.
Hope it helps
Our Acriche series of LED's work at your required 220VAC and at 50 Hz, Please take a look at our website www.acriche.com or join the Seoul Semiconductor Element 14 site for more information.
Most of the current range (and what you are looking for) are available as samples from Farnell.
Please take a look at the attached datasheet and feel free to contact me if you require any further information.
UK Sales Manager
Acriche AW32X0_pre00.pdf 240.8 K